The timer offers 6 options. I have just set to 0700, 0900, 1700, 2100, 2200, 2230. So there is no reason why it should call for heat at 0000-0005 on Saturday only. Maybe Speedfit will understand the logic?!
I have the same problem with my Aura configured as a wireless paired single room PRT controlling underfloor heating. I have reset the timings without any unprogrammed slots. I have set party mode to zero and as soon as timing hits midnight on the auto/night setting it turns the boiler on for 5 mins.