Hey stu
I'm in the same position as you. I'm also a fuel tanker driver and hoping to make it out to Perth some time this year.
What I have found out so far is you will have to re sit your class 1 again and also SLP (ADR) and a dangerous goods license.
spoke to a few drivers out there and they seem to think you could earn between $80 up to $160 pa or if you go up to the mining area could get $200 plus living expenses.
My plan is to join an agency till I get my dangerous goods license.
Where are you working in the UK fella