Census is decent, shows the couple I'm after in 1891, 1901 and 1911. Names all spelled the same, years all correct - model citizens! Burial records easy to find, only died in the 1920s-40s, Dad even helpfully pops up on a couple of the kids' wedding certificates.
Issue is, cannot find the marriage record between them at all. It's possibly one from 1881 with an obscured/illegible spouse - Familysearch helpfully suggests that Peter may have married William or John - but doesn't offer an option to look.
Nothing in the Lancashire records either.
Any tips for hitting this kind of wall? Without a maiden name I'm a bit stuck doing her line any further. Alas, her name's Mary.