Thanks all for your advice. I was interested in the Redline oils as had heard great things from the Ferrari sector as the 308/328 cars suffer from poor 1st to 2nd changes and lots of comments on how Redline had improved this.
Currently the GT40 changes well but it's the Esprit that is weak on second gear synchro so thought I would try and delay the inevitable and experiment.
Going with Redline MT90 GL4 75-90.
Trevor.