Ideally would like to find a good shop with really good service and excellent workshop. Was recommended Corley Cycles in Milton Keynes but I have not been impressed on my two visits.
Leisure Lakes in Daventry seem pretty good, can't be far from Northampton
Pitsford cycles at Pitsford reservoir.
Also Roy Pinks in Newport Pagnell
Pitsford Cycles provide excellent service and have a decent workshop with reasonable prices
I either use Leisure Lakes Daventry or Pitsford cycles. Both offer good advice and are helpful.
Chaineys in Shenley Church End in MK aren't an obvious choice for bits and kit,but they have always been spot on for mechanicals and wheel building in my experience.
Maybe a bit out of your reach as it's technically in Leicestershire but my favourite lbs is George Halls Cycle Centre. Better prices, quicker turnaround and friendlier service than Pitsford ime.
tom + 1
I'll second chaineys theyre a good bunch and tend to sort out the minor jobs (headset pressing etc) there and then where as Corley will tell you they're booked out.
I'd reccommend a visit to check out Baines racing if its near- its a unit on silverstone race circuit grounds. decent, small shop but friendly local service
good blokes, known for racing superbikes so the workshop is high tech and bigger than the bike shop.