Chris,
Sorry to hear you had no joy at your local branch.
If they've stopped doing them, it'll only just be recently I'm sure, as we put a couple through not an age ago.... I had a look on our D & P till menu today and couldn't find anything for disc! :(
give customer liason a ring on 0116 232 6111.
If head office can't help, try these labs;

Joe's basement 0171 253 3210 (London)
Central 01242 516188 (cheltenham)
Colab 01242 224219 (cheltenham)
The Darkroom 01242 239031 (cheltenham)
MetroColour 01453 825458 (stonehouse, Glo)

some of these numbers are a little old, so can't promise.
If none of these can do it, post here and I'll have a dig deeper through some directories.

Hope this helps