Wanted - two pair cable for 12VDC and RS485

I am looking for cable with two twisted pairs: one which can carry

500mA/12VDC power up to 80 metres and and another which is screened + twisted and suitable for a RS485 network. The cable will be used for a variety of applications - CCTV control, a small RS485 network including a security alarm keypad, lighting control system.

Is there something suitable available in the UK? (I've looked at Cat5 cable but would prefer not to use this for various reasons.)

Belden 1502R

has a 18AWG power pair and a

22AWG twisted pair. BUT it is only available in the US and can only be exported at high cost and in large lengths.

Would I be better off buying separate cables for power and signal?