Turns out it was not the head gasket (compression test shows that to be absolutely fine), but one of the water pipes had failed somewhere leading to the coolant etc getting into the oil and making a mess of things.

Well, I'm a bit disappointed about having to revisit this read.

After the issues listed above, having the engine flushed through, new water pump, coolant pipe, cam belt, thermostat, temp sensor etc, I hoped it had all been solved. However, the car is still getting through coolant. Not at a major rate, but particularly after a longer journey. There is also the return of the gunk under the oil cap, although I am making quite a number of short journeys so this could just be due to that.

I have had a thorough look round the engine, and can see no signs of an obvious leak, though I have noticed a patch on the drive after a longer journey where something has dripped from the engine, and it appears to be in the area/side of the engine of the cam belt and water pump. The coolant is clear, and there are no signs of steam/loads of smoke from the exhaust. It's just getting a bit annoying.

So my question is, is it possible that the water pump is leaking when it gets up to temp, particularly on longer trips, and is there an easy way to check this other than getting the car up on a ramp to look underneath? There have been no problems of less of power, very eating, low fuel economy, heater not working or anything else like that, just the loss of coolant.

Cheers

If you think the water pump is leaking again then I'd expect the garage who replaced it would do a coolant pressure test free of charge? As for the gunk, I've seen that amount before without it ever causing any trouble, although as people have said it's normally in cars that don't get much use. I believe that engine has a oil to water cooler (sits just above the oil filter if it has one)?? That's another possible place for coolant to mix with the oil if it's failing. They're not too expensive so might be worth looking into.