https://www.independent.co.uk/travel...-b1878373.html
According to this GovUK are technically wrong but it's the kind of risk no one wants to take.
As for turnaround times, I renewed mine back in May (losing 6 months into the bargain) and it was back in less tha 3 weeks.
This stuff causes so much angst with travelling I think we tend to err on the side of caution and of course pay up