A hole diameter of 25mm to 32mm is suitable for fitting the 7" tap and 30mm to 34mm is suitable for 8" wooden taps. A 38mm to 44mm diameter hole is suitable for fitting a 10" tap.
Thank you so much the barrel was a birthday gift for me from Ian. And it is lovely exactly what I wanted. The service and delivery was excellent. It smells nice too. Tuesday Burlingham