When we did the trip in 1972/3, I and my two brothers were on Dad's passport. As Dad's Dad was from the UK he got automatic entry, while Mum had to go through a different passport control queue.
And you're right about the pricing. When we were there the UK was switching over to decimal, so you had old and new pence in circulation. From my recent trips there, I work on what we pay in Australia in dollars and cents, is what you'll pay in the UK in pounds and pence. Even a pub meal isn't cheap.
@OZDUCK, it will be interesting to hear of your experiences, including recreating old photo scenes.