thats brilliant how you have got links on them high profile websites! time is an issue that i have. Writing a truly creative piece can take days which is the thing i struggle with most.
In terms on the URL...the URL has always been www.colourbanners.co.uk its just the structure of the deeper pages i.e. www.colourbanners.co.uk/products/mesh-banners all changed.
I don't know whether this triggered something, but there was a huge drop in August (ahrefs shows this pretty well)
I know there are some shoddy links - some of which i disavowed but with no manual penalty im treading carefully. I'm leaning towards it being a problem with the anchor text distribution.