NC heater only getting warm not hot

[MickAP]

Read my last post in the thread below re thermostat.

Coolant change on a MK3

I’m wanting to do a coolant change on my car… However I did this on my last MX5 and realised that you can only get about 3/4 litres out by draining the radiator alone. Can anyone suggest the best way to get most out? Would removing the thermostat address this?