Vee_Que There should be cheaper options available to you online through ebay. but shouldn't be worse than dayco,
AshDVS Due to my predjudices, I'd be wary. Gates-Gates and Calibre-Gates may or may not be the same thing. That said, its only a accessory belt and you do have two of them - it isn't like its a timing belt, so it'd probably be fine. They take no time to change. Of course, given their relatively low cost, I'd just end up using something known-decent and not think about it after fitting.
Dauntless Thanks for the input guys. I bought them today, as I needed them in a hurry. Unfortunately on a 740, one belt drives the power steering and water pump/fan, a second drives only the aircon, and a third drives only the alternator. I guess being new they're unlikely to let go without warning, so if they don't last I'll order something better.