A raised vegetable bed if it's not there already. Move that shed off to the side.

there are lots of plants for all seasons. start by looking through good reference books. the RHS ones are excellent. then decide on the ones you like and then construct your flower beds.
the 'wendy house' looks portable so that can go any where. rabbit proof fencing might be an essential but again this can be hidden with shrubs and plants.

think about permanent structures such as a rockery/arbours/pergolas etc.
then shrubs/trees some evergreen others deciduous.
do you want an area for soft fruit/veg or a greenhouse / pond?

do not rush into any decisions though many mistakes can be put right in time.

Look up Rabbit Proof Plants on the internet - well worth being selective in that position. You could have a great veg plot there, rabbits allowing. They wouldn't eat potatoes anyway, and runner beans would be fine as long as you protected the bottom the stems which you could do by growing through used plastic bottles with the ends cut off.
I would definitely have at least one Camellia in one of the places that gets morning shade. But first you have a fantastic opportunity to plan the landscape. There are internet sites where you can draw your ideas. Don't have the whole plot visible at once and think about a few changes in level. A satisfying garden has surprises as you walk round it., and and groups of shrubs or small trees would help to soften the wind. You might get landscape and planting ideas by visiting lots of other gardens if you have the chance.
Exploringthtis site might help too as there are lots of pics of members' gardens.
Don't be in a hurry - take your time.

Thank you all but not shown in the photo to the left top corner is a triple garage and a 42fttunnel. Tried growing out side but the rabbit's won,I have Tom's, cucumber, courgette,squash,potatoes, Corn on the cob, marrows all doing well in the tunnel. Hubby likes it open but I want some colour, dont have time for a lot of weeding as it takes 4 hrs on the ride on to cut the grass. Summerhouse intentionally placed there as in the Sun for breakfast and shade for afternoon cuppa and book, looking to put shrubbery patches either side

Wow, lucky you, a completely blank canvas... this is what we had when we moved into our present home in 1990. SBG has given you some very good advice, much better to take things slowly rather than having to undo something you've already done. If you want to grow veggies great, if you don't, don't; same with Stera's suggestion of camellias.

If you have children or pets you may want to create an area of the garden that is mainly for them.

It took us years to create the garden 'we' wanted... and we did lots of looking and thinking and talking and visiting other gardens and asking questions. We still made mistakes, putting a pond under an ash tree, but we learnt from them and moved along.

Only you know how much time you will have to garden and this will also have to be taken into consideration as you make changes.

As you remove the turf turn it upside down and stack it in a corner and after a year or so you'll have wonderful loam!

Good luck and look forward to seeing photos was you progress forward!

Ok i thought it just a tool shed.

Wow lovely, I think I would have to have a long border across the bottom growing grasses and perennials like 'prairie style' and lovely 'hot' colours like oranges, purples, reds, etc but then it does require some planning check what type of soil you have and choose plants that like full sun, I have done similar in my south facing much smaller plot, Stipa Gigantea a good grass and lights up when the evening sun is on it, happy gardening !!