My 97 S1 seems to be 'sipping' coolant. Should I be worried? It has gone from the Max mark to about half way between Max/Min in 3 weeks. Not driving too hard but including the recent hot weather and about 1000 motorway miles (250 miles a trip M6 is pants!) I have read alot about Elises liking to sort their own levels out but also alot about the dreaded HGF. I have none of the classics (Mayo/steam/high temp).
Should I be scared?
It's still under warranty but thats from Bromsgrove, at least £60 in fuel and 2 days off work....!
Any options? I do have AA parts and labour, so do I just run and monitor until things get worse ?

I should have access to a ramp tomorrow so will get the trays off (If I can!) and check for leaks and rad damage......
Thanks y'all
Rich