'UAE and Bahrain are different, you do not need and exit visa. Look at the stories of 100's even 1000's of cars abandoned at the UAE airports when people have fled the country.'
Disagree - the UAE is very similar to all that has been described.
A residency/work visa has to be cancelled before you can leave UAE...and that means handing over your passport, the property of the UK govt, to the slimeballs but get the bit about cars with HP being abandoned etc. Those people will never get back in. Bouncing a cheque in UAE gets you some prison time.
Moral - try and convince UKPO that you need a second passport.