I always use Steve at AA for parts that he sells, might not be the cheapest but he has good items where places like ECP sell on price - I use them for some things but would far rather support Steve who is a real Coupe enthusiast and invests in stock which helps keep our cars on the road.
As above Steve is a good source for parts and knows his stuff.
I would not be in a hurry to recommend some Birth parts though - especially (rear) wheel bearings which have been failing regularly - I went through 4 in quick succession and ended up with SKF