I think you will find you can fly in the UK on your OZ licence, but most (ALL) clubs will want you to have a checkout before they let you fly without an instructor. Most 4 seaters will cost you around the £100/hr mark. Don't know about other types but Vectair (www.vectair.flyer.co.uk) at Goodwood (Chichester) have a 4 seater Robin that would fit the bill and is a nice machine to fly.