couple of things to try, fitting an oil cooler, not the ford oil warmer, but a proper mocal type one.
also disconnect water cooling to the turbo, just let the engine run on a bit after a hard run, you'll see a big drop in water temps and won't really affect the turbo's life span.
i run a 1.8 zvh, was running 190bhp or thereabouts i didn't have any overheating problems at all, this is on my mk2 fiesta, with standard rad.