You have a good size plot about the same size as ours (which we have had for 10 years) and you could get enough fruit and vegetables to last you through the year.
It would be a bit boring to eat only what is in season but if you are prepared to cook. Freeze what produce freezes. Make meals to freeze or make jams and pickles then that would give you a good level of self sufficiency.
It is possible to get fresh vegetables all year round. Winter is the most difficult but with Brussels, savoy, kale, winter broccoli, leeks, swedes to name a few you could be reasonably sufficient.
Storage of roots is something to organise before you harvest too.
You wont suddenly become perfect with all the things you can do. It would be a full time job, looking after the land, the storage and the kitchen to become totally self sufficient. People who have small holdings and can survive on what they grow have been doing it for generations and still get problems with what they can not control. Like the weather.
A lot depends on how much you know about growing. What standard of living you expect to enjoy and how well you can cook, make your own wine and cordials even.
We have some trees apple, (eating and cooking) plum, pear, cherry and a newly bought peach.
Grow rhubarb, strawberries raspberries, black and red currants, blackberries and a mulberry.
Last year the rain was too much for my onions and I lost some of these, so, for the first time in years I had to buy onions. My tomatoes and potatoes got blighted.
Otherwise I would have had a lot of things like shepherds pies and tomato based sauces for pasta, frozen.
I have plenty of jam and pickles left though.
It is a not a perfect science. One year you get a glut of what you failed to grow the year before and visa versa.
The main thing is to enjoy what you are doing get a comfortable chair on your plot to take a rest and provision to make a drink when ever you need one. It is supposed to be fun with a bonus from the harvest.
