Many clinics and sex worker projects distribute Pasante and they do a narrower ('Trim') and wider ('Large') size.

A quick search reveals you can also get the Trim ones on Amazon, where it's very amusing (OK, to me anyway) to see them offered 'used & new'! 12 (new) for ?6.50 including postage.

A better search finds http://www.freedoms-shop.nhs.uk - Camden PCT's service - which sells 144 Trim or 'King Size' (Pasante have a habit of changing things every so often) for ?20.86. They also do Durex 'Close Fit' (= narrow) for slightly less, and Mates Conform (= narrow) for even less.

(The pricing slightly surprises me - one of the reasons Pasante was popular with PCTs supplying condoms to projects was that they were cheaper...)

We've also got Lovehoney, as recommended on the main Saafe website http://www.lovehoney.co.uk/sex/condoms/