Installing auto vent opener on greenhouse

[princeperch]

I managed to snag a cheap greenhouse from b and q - 4x6 with horticultural glass. Rather oddly this greenhouse didn't come with the facility to install an auto roof vent. Whilst it might be wishful thinking at the minute I'd rather like one.

Is there anyway to do a bodge install for a roof vent when the greenhouse wasn't actually designed for one ?