The above photograph is not mine it belongs to Juliet Davies from the Allotment Junkies Facebook group. It is a classic illustration of why this type of temporary cheap greenhouse are nicknamed Blow-A-Ways.
My suggestion to Juliet was to drill the wall and put in 2 eye bolts one either side of the greenhouse and put a rope or bungy cord with hooks to hold it back tight to the wall
Here is a photo from 2016 of my Plot on Spencer Road with my blow-a-way with bungee cords to eyebolts fixed to the shed and there are also soft bricks (plastic milk bottles filled with dry sand) to assist in holding it down.
I didn't originally have a cord long enough to go from hook to hook so there are two chords holding the greenhouse tight against the shed.
Mill Green 2015 and a large Blow-A-Way up against the wall to grow tomatoes in, but this had soft bricks at each level, cable tied to the upright members so 3 bricks each and 9 in all. Plus tent pegs over the bottom horizontal bars.
I'm going to be using one of these in the back garden shortly the Bio Green ARTIC 100 which does come with tent pegs and has fixings for holding down to soil.
I shall be using a paving slab and some weight inside to try and stop what you have seen at the top of this post from happening.