Hello Chris,
If you have your own transport, you could always try the Bure Valley Railway shop at their station at Aylsham (NR11 6BW on the sat-nav), a few miles down the A140 in the Norwich direction.
Was in there a couple of weeks ago when as usual, they had good stocks of Hornby, Bachmann and Peco at very reasonable prices. Could be worth a visit!
HTH
Rob
PS, forgot to mention the Graham Farish and 4mm scale die-cast cars too!