Triumph TR6 first service after rebuild

The TR6, the engine of which I recently rebuilt, has already covered 500 miles so the owner brought it in to have an oil & filter change and a re-torque of the head bolts, as well as a few jobs that need either correction (a leaking timing cover seal) or investigation (poor hot start, possible fuel vapourisation in the injector lines). I'll also be fitting a fuel tap on the tank outlet and a low pressure filter between the tap & the pump. Other than that the car is reported to be running well, he wants it back for mid May as he's got a few hundred more miles to do on some club runs. I'm also flushing the cooling system again, I don't know what the previous owner used but it's a devil to get out, even though the engine was stripped and radiator flushed, there must have been something hanging around in the heater core.