Charley,
£1000pcm is accurate. Certainly this is what Easyjet pilots get for the first 6 months as technically you are not employed by the airline during this period. Other airlines do vary, for example you may get less of an allowance from CTC but you may qualify for flight pay from the airline. All in all, it will end up around £1000 tax free. Chances are though, having passed the AQC, you will go to Easyjet.
This is why the airlines like CTC! They don't owe you anything until the contract is signed. Instead they pay CTC for the "use" of one of their pilots for these six months and CTC pay you a very modest allowance. Of course nearly all get employed at the end of this process.
This particular arrangement is very useful for charter airline's who maybe only want a pilot for the short term to plug a gap without any commitment.