Hi Vinny, yes I'm keeping a close watch on the night frosts, like you say, ok so far.
I made a small greenhouse from cheap wood and some horticultural polytunnel type plastic. It doesn't hold the heat at night, but it gets nice and hot with any sunshine during the daytime. The house i'm renting has an east facing conservatory, so it doesn't get lots of sun but it does remain frost free in winter. If housing ever becomes affordable I'd like to buy a place and build a big greenhouse, there is a very inspirational guy from the states (Jerome Osentowski) who is designing passive solar greenhouses that store the summer heat in the soil all winter (he calls it a 'climate battery'). I'd love to build one and fill it with fig trees, grape vines, peaches etc
Cheers
Steve