[Yorkie]

I wouldn't advise growing potatoes on it as they'll probably get scab badly. I'd probably try and remove some of it perhaps gradually, and introduce some fresh soil. Either from the other plots if the topsoil on them is deep enough, or import some from elsewhere. In the meantime try growing a few various things and see how they do. You could always dig a trench out and fill it with better soil and try runner beans or something.

Potato scab is a bacterial or fungal disease (depending on type), aggravated by dryness or alkalinity.  Therefore there is no indication that the particular location described here will trigger scab.

[alimilly]

My original plan was to put permanent planting in this area,  but as I anticipate the brambles will grow through I thought this wouldn't be the best place for the fruit or rhubarb.    I'm hoping that with each digging I will be able to keep them in check and wear them down over time. 

I'm guessing that as brambles and nettles have been growing here  that with a with a bit of TLC and fingers crossed potatoes should be OK too?

[Yorkie]

I see no reason why the plants won't grow once you've got rid of the brambles.  Nettles are persistent wotsits - I nuke mine with weedkiller as the roots are easy to overlook.

[alimilly]

Thank you Yorkie for putting my mind at rest about scab - that was another thing to be nearly worrying about!

I am doing my best to get rid of the brambles, but having read somewhere they will re-grow from a 1/4 inch of root - I think it will be a forever job to completely get rid of them!     This year weedkiller will be used!