SJSC have a good range, you're likely to need these http://www.sjscycles.co.uk/product-Tektro-Tektro-R556-Dual-Pivot-Caliper-Brake-55-73-mm-Very-Deep-Drop-Nut-Fitting-79.htm to run 700c wheels in the stock fork.
@gbj_tester started
London Fixed Gear and Single-Speed is a community of fixed gear and single-speed cyclists.
SJSC have a good range, you're likely to need these
http://www.sjscycles.co.uk/product-Tektro-Tektro-R556-Dual-Pivot-Caliper-Brake-55-73-mm-Very-Deep-Drop-Nut-Fitting-79.htm
to run 700c wheels in the stock fork.