You could try asking Gates themselves where to buy from:

"Dean,

If you telephone our warehouse distributor in Birmingham - Ferraris
Piston Services on 0845-456-3266 they can advise you of a local stockist
who could help you. Ferraris supply motor factors with our products all
around the Birmingham area.

In order to tell you what kit you need the factor would need your
chassis number and engine number. They use registration mark look ups
so, should be able to find this out from your number plate.

Best regards,

Iain Mitchell
Technical Coordinator, District Sales Manager - Ireland
Automotive Sales

Gates Corporation
Tinwald Downs Road

Dumfries, Dumfries and Galloway DG1 1TS
(44) 1387 242075 Tel.
(44) 7774 615270 Cell
IAINM@gates.com "

 

I'd change the idlers and tensioners as a matter of course; the last thing you want is to buy just the belt, then find the tensioners/idlers do need replacing after all - or worse still thinking they dont need replacing and then having them fail later down the line!

I paid £130 inc VAT for my gates kit last year, but I asked a mechanic friend of mine who had a trade account to get it for me... However I'd ring round all your local motor factors and take it from there.

 

there are gates ones on ebay mate very cheap too

 

My motorfactors place nearby to Oxford quoted me £119 for the kit, thought that was pretty good