AED is "pegged" to USD (as you probably know)
The market's view of interest rates has changed so over the last few days USD is lower against GBP ie you now get about 1.87USD to 1 GBP.
Because of the peg, that means you get less AED for GBP also.
In other words, GBP/AED will move in the same way a GBP/USD.
I have a payment coming up too. I'm not sure we will see an exchange of much over 7 AED anytime soon, so I think it is a case of getting the best possible exchange over the coming week.
You can see the exchange rate trend here...
GBP to AED Share Price Chart | GBPAED=X | | Yahoo! Finance UK
I hope that helps.