Did my first track session yesterday at Blyton Park with Car Limits (4 person day). Great day learned loads (and will probably forget most). On my last few laps (with just me on track ) things started to hook up well unitl I realised that I had lost my brakes. The pedal just went flat to the floor, so I pumped it and got a little bite, but at the next corner nothing again. Back to the pits and left to cool off until the drive home and all was fine.
Did I boil the fluid and if so does it need replacing immediately?
Certainly sounds like you’ve boiled the fluid. Replacement is advisory before you think about getting it hot again. But as you said, the drive home was ok so you’re not in immediate danger.
slightly cheaper but it boiled at Brands on about it’s 5th track day. I think i would go with the Motul 600 next time but the rule is that you have to bleed some through regularly if used on track.
I think I recently bought 3 litres and it all went on the Elan and Exige, ie 2 systems fully flushed. If you are going to do stuff at home regularly just order more than you need to save the postage
) things started to hook up well unitl I realised that I had lost my brakes. 
The pedal just went flat to the floor, so I pumped it and got a little bite, but at the next corner nothing again. Back to the pits and left to cool off until the drive home and all was fine.