It has been rumoureed about here for a while now that Monarch will be moving to T2. I was speaking to a bloke from the airport authority not long ago and he said it is all but confirmed. I suspect it will be in November, given the above.
He also said at the time that Monarch were looking for a lounge there too. It does make sense as I know they are currently reviewing the benefits of their frequent flyer Vantage clubcard holders, after withdrawing complimentary lounge access a couple of years ago.