Think it's these:

http://www.ebay.co.uk/itm/3x-1-4-Fle...item4ab28737cb

If they're not well aligned then they will probably break do to metal fatigue.

So you'll have bought 7075546, 7075522 and 7002555...£16.28 per coupling.

From bearing station a 15T and a 30T HTD timing pulley plus 64T timing belt costs £15.55, £17.05 including postage.