Here’s what I would do.

1. Get rid of the paving on the left. It’s too small to act as a seating area.
2. Complete the horseshoe shape of the lawn by bringing the curve down to the top of the handrail.
3. Turf the lawn.
4. Move the clothes line which dominates the garden. Can it be moved to behind the building on the right. If it has to stay there, tuck it out of the way somewhere when it’s not in use.
5. Create a seating/hard surface play area on the patch of soil in front of the brick wall where that green netting is. Maybe re-use the paving slabs once they have been jet washed.
6. Get rid of the messy collection of pots on the wall.
7. Move the bird bath somewhere more visible and put a bird feeding station near it.
8. Find a better use for those cobbles. They look like an accidental spillage where they are.
9. Change the steps into a graded path. Chose a slip free surface such as ashlar or bark clippings.
10. Paint all the fencing dark grey
11. Create a huge bed of dark red cosmos eg Rubenza on the left hand side.
12. Divide that huge clump of geranium(?) on the right and have the smaller clumps as a running motif through the garden.

I must say that you have explained each and everything in very details also I have been thinking to do it with verities and give a call to do it even I have found something special here Delivery flower Ukraine which can give you a perfect call