Maybe try an upholsterer,I bought a set of leather pants off trademe,they had a piece open on zip by the crutch,cost $35 to repair,they may be able to fix for you,the liner should be ok with home sewing machine as not seen,but outer needs to be waterproof and roadproof (heaven forbid).Even try a saddlery shop,as option as they do covers etc with canvas so have machinery.
Bookmarks