Now that In have a heater in my greenhouse to keep it frost free should I still put up bubble wrap or will heater be fine???
Depends what you are planning to keep in there and for how long.
I use both, if your heater has got a thermostat it will not have to come on so much if you have got the greenhouse bubble wrapped so saving you money on heating.
I use both.
Planning just to over winter plants & cuttings--sounds like last year I did correct as used both.!!!!