You say you have a Class 1. Does this mean you have considered civvie flying? I know of a few people that joined, left through training and went the CTC route. It may seem expensive, but if you see the cost as an investment, then it is worth it.
You have nothing to lose by giving the FAA a go. I'd research career routes though if your aim is to fly and you join the army.
Helidriver - are you sure? Unless I am mistaken, I've come across a few pilots who failed RAF but entered the FAA.