Many thanks for all your replies. They are much appreciated. As a matter of interest, the steep turn normally required as part of an instrument rating test is based upon 45 degrees angle of bank and 250 knots. 60 degrees is real Gung Ho stuff and not really relevant other than unusual attitude practice.
Opinions vary, but some pilots prefer not to use the stabiliser trim in steep turns. One reason being steep turns are usually short term manoeuvres and if back trim is used during the turn to off-load the control force, rapid forward trim as well as slight power reduction is needed when rolling back to wings level. It can get complicated especially if conducted on instruments.