I used to fly this route quite regularly out of London and Manchester - DYKWIA is correct, ex UK is a lot cheaper than ex DXB. If you purchase a flex + ex UK you can just put your rtn as far forward as possible then keep changing it when you know the precise date you will need it - also this ticket type is your greatest chance of op-up.

As far as flights go this is quite an easy one and I have done it that many times now I wouldn't dream of paying J prices to DXB, I wouldn't even use miles to go there but thats my personal opinion (more cost effective using them on long haul).

There is an emirates credit card you can get in Dubai.