The "Jill" greenhouse measures 4m long by 2.8m wide - it should just fit this space perfectly. The owners have a lot of land here but garden wraps around the house and has a lot of sloping sections. This spot is pretty flat - it used to be the site for a raised swimming pool so it's well compacted. I found quite a few reinforcing bars of steel and plastic sheeting whilst digging out which I removed from site.
The foundations are solid concrete block laid on a wet mix of concrete. This helps me ensure the foundations are perfectly level and I can start bricklaying almost immediately.
I removed the rest of the soil inside, laid weedblock sheeting and paved over. The cold frame sides are finished and the inside is laid with weeblock and gravel for no maintenance and good drainage.