Welcome to the Forum,
unfortunately, patching the roof, really wont help much, as if its the OEM vinyl, it will shrink and harden, and will continue to get worse.
when i got mine, i factored in the price of a new roof.
the best place in the London area to get it replaced is Carhood Warehouse...the mohair option is the the best as its will give a 15-20 year life and will remain flexible and in good shape.
the only down side is its £800 fitted, but i can say from personal experience its well worth doing