Thank you all for your comments. There is method to this madness called boat repairs. The epoxy glued washer idea is just brilliant have filed that away if there is ever a repeat performance. Half my problem has been doing this solo, another pair of hands would have helped massively. Put the usb camera inside today to have a final look and the rivets and washers were tight on the inner wall but one of the bolts hadn't pulled up tight enough so levered the top washer up and then tightened the nut down and something went right for a change and it bedded well.Test sail tomorrow so will see how we go