Short answer: No its never too late.

People rescue lost links in this way all the time. The old pages may not have been de-indexed yet especially if there are being linked to from another website.

Ideal solution: Locate all the links pointing to old pages and get them updated to point to the new page. Put the 301 in place anyway to save any you miss.

Nearly ideal solution: Slap a 301 redirect on it - BUT make sure that the 301 is to a direct replacement / relevant page.

There is no negative implications for doing the 301's this late... (as long as the pages are relevant). But not doing them... well as you have seen... rankings will suffer.

Ive seen links that are months to years old get rescued this way, so get them redirects on!

I agree with Andy,

I use it as a guidance tool on any website i build. It serves a purpose, to check things are understood how they should be by a predetermined standard. But like any other automated tool it compares to set requirements that cannot always be met and cannot identify and ok these exceptions.

As long as you understand the error its pointing out and why its pointing it out, and know that despite this the code is rendering correctly and all outcomes are working as expected then there is no problem.

From an SEO stand point, aslong as google see's your site how you want it too i think it is a very very minor factor. Hell all of google returns errors of some variety.

Hi John, sorry ive been on leave so not checked back on the  forums.

Glad it looks like its working for you. I dont think the comments do anything except signify where word press has begun writing to the .htaccess (i dont run wordpress so can't be sure). Normally comments do nothing but signify something useful to the user.

I can try to breakdown the code a little for you, but my htaccess isn't fantastic so its by no means complete.

Firstline:  RewriteCond%{REQUEST_FILENAME}!-d

RewriteCond% = This says use this condition if....
{REQUEST_FILENAME}!-d =  ... is NOT a directory

RewriteRule^(.*)/$ /$1 [L,R=301]
I believe this bit takes a snapshot of the url upto the final / then rewrites it to that snapshot.

The combination of these must mean it doesn't affect your wordpress admin directory. I know this code can break if your install is within a directory (as is discussed in the stackover flow link) but they have provided a solution for that in that topic. I would say test if on your live website to make complete sure it will work as this may be slightly different to your local install. Have a back-up ready just incase it doesn't.

Make sure you check every url including

Homepage
Pages
Posts
Category Pages
Sub Category Pages
Post Pages
Any images or files

To make sure it is working as expected on all of them.

Hi John,

I asked something similar myself something myself but im on the Magento platform. This should matter as the solution wasn't platform specific. It just involved editing htaccess file. If your up for editing your .htacccess file then it could be of some use. The topic URL is below and it contains multiple solutions for editing and removing the / and the debugging process we went through along the way. (Courtesy of Andy and Dirk) Hopefully its of some use to you

https://moz.com/community/q/cms-pages-multiple-urls

SUMMARY:
If you know how to edit your .htaccess and your ready to dive straight in this code should do it.

RewriteCond%{REQUEST_FILENAME}!-d
RewriteRule^(.*)/$ /$1 [L,R=301]

If you want the page with explanations and walk-through please see the original topic as editing your htaccess  badly can cause all sorts of errors.

Edit: I realised i was probably a tiny bit lazy and should of probably included this link which is the original link i got sent from stackoverflow with instructions on how to to edit your .htaccess file.

http://stackoverflow.com/questions/21417263/htaccess-add-remove-trailing-slash-from-url

Dirks answer later in the post offer guidance on applying it to certain parameters which should prove helpful if your still having loop problems with the admin page.

Sorry i should have been more clear. This php solution is not a solution, at least in any practical sense.

Basically you would have for example

Descriptions Stored in variables
Meta Description UK
Meta Description USA

The page HTML would be

but the user is already on the website... they have already passed any point the meta-description would have been displayed to them.

The problem with this is that Google displays the meta-description that it has indexed from is most recent crawl. When google crawls your page is loads your page as if it were a user from wherever the bot is located, so wouldn't be able to see the other meta-descriptions for other counties and so couldn't display them if it wanted to.

Even if it crawled your site for various places around the globe, it would just be constantly tyring to update. It can change but each time it does is takes a period of time to be reflected on google. Once its changed the old one isn't stored, its just replaced. Its kinda a 1 description per page rule.

The only solution i could think off is a different landing page for each country (which you have) but there isn't a way to have a dynamic meta description on your main .com (as far as i know) sorry

To my knowledge there isn't

Are there are ways with php to dynamically load in a different meta descriptions? Sure.

The problem is that this wouldn't be reflected in google. Google takes days-> weeks or even months to update a meta-description within its index. So even though you could make the HTML code change on the actual page, it wouldn't change on the search listing nullifying the whole point.

I don't believe an option exists around this, but somebody may know something i dont.