They are training at full speed, but they didn't recruit for three years and they're not going to make up the slack in 12 months. The requirement to accept Draft Assign is in Bidline Rules (BLR). You will need to track down a personal copy when you join. Thats the 'Agreement' to which your contract refers, and by signing the contract you agree to the terms of BLR. It is not possible to refuse it unless you want to be suspended. If you're going to LGW then disregard the above as BLRs don't apply there.