Is it far to early for UK greenhouses?

Yeah they should be fine it's the night temperature that will catch you out buddy but in all honesty they should stunt in size slightly but overall you should end up with a satisfactory result and maybe some nice stuff colour as cold will shock it purple/blue I'm North East UK and I put mine out day light in night for further light time and better growth plus the temp is better indoor on a night just don't let the room be warmer then the day temp lol not sure what that will do but I know it's not advised

If its in a Greenhouse it should work without Problems i think, safe bet would be around April (maybe...)but if the temps get lower again you can always cover them in the night so sure go for it.😋