Don't you believe it! Mine went up after terrible bricklayer did two courses of bricks for it which fell over - more sand than cement! Brother in law, laid small layer of concrete for footings, laid course of two bricks - nice and solid - proper mix and spirit level used frequently! And bingo, beautifully anchored greenhouse.
Actually, did lay a little brick wall meself which is still standing! Amazing what you can do with a little determination, the correct mix and a spirit level!
Dispair not ;D