I don't know how it works over in the UK, but here in the States, I can run a PPC campaign with a generalized keyword "web design" and only target specific zip codes, cities or county (through Google PPC), and even more granular based on hobbies (in FB).

So, yes, I would do the generalized, and then if you can, spread it around the several different geo areas that you can target.

Good luck!

PPC landing pages and SEO landing pages ARE NOT THE SAME!  Nor should they be treated the same.  Sure, every page on a website that is exercising SEO should be treated liked a "landing page" - but not in the same way.  Let me explain.

SEO Landing Pages When you have rolled up your sleeves, written your content, worked it to a Flesch-Kinkaid grade level and optimized it, it would be a total bummer if your visitor couldn't convert.  Conversion could be, reading the next blog page, next blog article, signing up for newsletter, signing up for trial offer, or actually buying x. In other words, on an SEO page, there are lots of options for conversions or browsing beyond the actual page itself, including bookmarking for later reference.

PPC Landing Pages Now, let's take the visitor who you paid to visit your website. Those visitors, you don't want them to browse or look around, you want them to buy or convert RIGHT THEN AND THERE!   That conversion should be there only option.  There should be no other leaks out of the page to keep browsing and tire kicking... either sign up, enter email to download, start the trial or buy RIGHT NOW, or back out.  Those pages should have the on-page meta done OK.  They clicked on your ad, if written properly, because they wanted to buy/try/sign up right now.  The page needs to have enough content on there to help them make the conversion and actually convert.  But not so much that it deters the conversion.These are the pages you can roll up your sleeves on and have fun testing with A/B conversions, customizing meta, etc...  One well written landing page can serve the purpose for several, if not a handful of keyword ads. They key is that the content (message) needs to match the intention (ad).  So, if your ad promises a free trial for white apples - then your LP better offer a free trial for white apples.  However, if you ad promises super cheap white apples with free delivery, don't take them to a landing page that offers a free trial for white apples.  Capisce?

I hope that makes sense.  Good luck to you!