Well, Demon have cancelled my order due to my distance from the exchange (a total of 1.6km!!!! - I've heard Demon can be a pain in the a*se in this respect), so it looks like I'm back to square one.

I'm still considering Pipex, but think I've now narrowed it down to the following :

Zen (although £24.99 is a bit steep for 512Kbps these days)

Metronet (still not completely sure how this works - need to read more);

Freedom2surf

Pipex.

Of course I'm sure you'll be wanting to recommend a 'friend', won't you Hex Spurt, assuming I go for Pipex??!!! 

I still have a dial-up account with Onetel (not recommended - shocking connection quality) which costs me around £11 for free evening and weekend usage so broadband seems quite cheap these days in comparison!