To update this further the 10mm belts are a option but the original is nearer tp 12 or 13mm in width. A 10 works but does not have the life of thicker belt apparently.
This is most likely why alot of people report squeaky belts on d24's as the belt will be 10mm
Another forum member has given me the part number from a uk site that do the alternator belts for a reasonable price.
The part number is XPA1132
https://www.ebay.co.uk/itm/174567463...sAAOSw5EdbH5mU
UK ebay link
Usa link
https://www.ebay.co.uk/itm/121951758...Cclp%3A2334524
ACCORDING TO UK site simply bearings this belt is 1150 long so should be the right one