So this is something I haven't come across before! My bitch was mated on 19th April which would make her 25 days if she has taken, which I suspect she has but cant say for sure yet.

However, today she has taken a mad notion of humping my leg and flirting the way she did in heat just before the flagging stage! Wanting her lower back scratched etc. I'm presuming this is just a normal hormone surge. She isn't a maiden bitch but I didn't keep a diary during her last pregnancy so I cant remember if she has done this before.

Anyone else ever come across similar behavior?

I feel that your initial thoughts are correct.  It's going to be all about hormones.

Thanks for your thoughts Jean. It could be normal for her after heat but  you know how we study them at this stage