Any recommendations? Cars used daily, so fast road, hard braking, some track days! Next is nurburgring on 24 of this month

The clutch is hydraulic so uses your brake guild I believe mate, use a decent fluid maybe something like ATE super blue!

You need to worry about the quality of brake pads too.

I use motul rbf 600 brake fluid but have used halfords own brand with no problems.

Upgrade to DOT5.1, cheap and higher boiling point and safe to use in a system that's had DOT4 in it previously.