Has the timeline changed? The averages were around 54 days.
Last summer around this time, wait for non-priority shot up to 5 months. Sheffield now processes a lot more countries than it did before. Priority, which never before went longer than 5 weeks, is now taking up to 8 weeks (or more).
So, based on all of those indicators, I'd be hesitant to make any plans for non-priority taking fewer than 12 weeks.
You can do whatever you want. I hope I'm wrong. But at the very least, please don't make any flight reservations.