If it's a well-loved device, surely it's worth getting a bit of tasteful, loving repair carried out?
...or find someone with some welding gear to fix it?
One of the many pluses of the otherwise uber-heavy Pashley is the steel frame, which anyone with a modicum of brazing experience should be able to fix. Unless I'm misinterpreting the pic, it looks like the lug at the top/steerer tube has fractured, not the top tube itself. If there aint enough material left in the lug to make a good join, getting a new jub should be simple enough - though might be easier to get one from an old Pashley of the same type than ordered new.