Sorry Dale, been away for a few days...
The belts turned up on Monday so very quick service! As expected they don't feel as 'supple' as the kit belts, but still perfectly useable. If it turns out that they are causing some drag on the drivetrain then out comes the old sanpaper
I'm not at the stage of the project yet where i can hook all the belts up, but running them over a pulley they seemed to sit on there fine.
For the price they are perfect and i think they'll do the job perfectly too.
Thanks again for the link.