I recently bought a property with unregistered title. The solicitor quoted his fee not knowing whether it was registered or not (though being an experienced solicitor he possibly made an educated guess as its not rocket science to know which properties might be unregistered). He made no extra charge or even considered it. I did say something like "oh god is that extra work?" and he said "not at all - Land registry is easy to deal with nowadays". So no extra charge and no idea at all that vendor should be responsible. I find the circumstances outlined quite bizarre.