Hello Dom,
Apologies, but I cannot help you with independents in your area.
What might be worth a coat of thinking about is what you are going to achieve in the longer term by not getting this done at the main dealer. This critical application should certainly not be treated as a cost-is-king job. Yes, you may get it done cheaper, but most importantly, what make parts are going to be used. Aftermarket (with the possible exception of Gates) are very much second class options, and I certainly would not use any other pump apart from a VAG dealer one - simply asking for expensive, written off engine possibilities.
Having said that, the 'bonus' of 'free' MOTs for life!???
Oh dear! Might be worth looking up posts by Welsh Sue (I think) when she got involved with this 'deal' .
Good luck and kind regards,
Gareth.