Birthday Celebrations

[FedupALMOST40]

I find birthdays really difficult and would like to be abroad for my 40th, I've had a really shitty 5/6 years so I'd like to be away for my actual birthday but it falls in the first week of school term.
I'd like to go for a week but school makes it difficult (DS starting Y11) so thinking the weekend of my birthday instead.
Any suggestions for somewhere warm and quiet/relaxing in early September for a swift break? Would be myself and my husband (or I might leg it and brave it alone!)
Can fly from Birmingham or Bristol but would prefer a shorter flight if possible to maximise the time.
Could be UK if needed, I would prefer abroad but understand the short window might make it difficult.

If DS isn't going on the holiday why not go for longer? Why does school starting impact how long you can go for if he isn't even going with you?

In terms of location early September is the best time to visit just about anywhere in Europe. It's still warm, but not too hot/crowded. Do you want a city break or beach or lakes/mountains? Italy has a good mix of all three and is nice in early September, also short flight time. I'm going to suggest Sorrento/Amalfi Coast.