What sort of plane is it?
£142/hour sounds about right of a Warrior or Archer but a little on the high side for a C150/2.
Having said that though the current dual rate at my home airfield is £147/hour in the C152 and £151/hour in the PA28 (I think the PA28 price represents an economy of scale though as the club has about six of them against only 2 C152s). That is in the south though
.