Just brewed a Coopers Bitter on Saturday with an OG of 1042 (ish), by Sunday mornning it was bubbling away vigourously (with a heating belt on) then by Monday, no (or very little) activity. Just done a hydromoter test today (tuesday) and it is 1008. Tastes fine too

Is this normal? and despite the lack of visual activity should it be left? Do i need to get any more action out of it or has it done most of it in first 24 hrs?
Any assistance appreciated.
Cheers