Hello, I think you could say that using the back of the summer house as a boundary feature is not a good idea because you are agreeing the boundary is a party one, with shared ownership and responsibilities. Clearly, the rear wall panels of the summerhouse are intrinsically part of that building, not in the nature of a party fence. It could lead to future disagreement and so it is best to have a fence, even if the summer house is immediately abutting it.
Yes I agree. It seems an odd idea. I suspect its about cost and him being able to access the rear of his summerhouse for painting etc if needed. Also given that it is immediately outside my conservatory it may be difficult explaining to any future purchaser that the boundary fence is his summerhouse and you are right could cause problems in the future. Thanks for your response. I suspect I will end up paying for it however I van now present a solicitors perspective. Thanks