I had a problem with my 2001 Freelander (1.8 petrol), where the top heating matrix hose sprung a small pinhole leak. I repaired this with pipe hose tape and about a week later the bottom heating matrix hose split about two inches at the bottom of the pipe. It was quite a bang and the usual cloud of steam so I had to get towed to a local mechanic as the coolant emptied out. I got 2 new hoses for top and bottom which were fitted on Wednesday - driving this morning and there was a hiss of steam - had a look and there is a puddle of coolant and the cooloant level has dropped. Could be a leak from one of these hoses again! Had the thermostat checked when the hoses were fitted in case it was stuck and it seems fine, but something must be causing this pressure to build up. Heater has been working fine. Any ideas?

Head gaskets are notorious on 1.8 k series save time and money by asking for this test

Ask the garage to put gas anylzer under bonnet, start engine and you will get background Hydrocarbons.

Hold probe over open expansion tank and if Hydo carbons jump it is head gasket.

Head gasket test fluids are a lot less sensitive than test I suggest

Any excess pressure should lift the cap on the expansion tank to relieve it, you could try another cap.