No bank holiday falls anywhere in the United Kingdom during September, and none does in October either. In England, Wales and Northern Ireland the run from the August holiday to Christmas is the longest gap of the year; Scotland breaks it with St Andrew's Day at the end of November, but nowhere else does.
Leave in September 2027 suits anyone not tied to the school calendar. The holiday season has ended, the weather is frequently better than August managed, and no public holiday anywhere is competing for the same weeks.
September 2027 runs to 30 days and closes the third quarter of a year of 365 days. One quarter remains, and it carries the clock change, both November commemorations, the Christmas break and the turn of the calendar year itself.