Right so im now tearing my hair out!!!
My bitch was mated on the 4th and 6th August so today is 64 from first mating and 62 from 2nd. She had her last litter 63 days from first mating. Have taken her temp this morning and it is 37.5 (99.5)... how long do i let her go before I take her to the vets, she is ok in herself eating and sleeping... pups are still moving around and can feel small movements from them...
Help

What is usual in her breed, do bitches tend to go to 63 days an over.  did you blood test for ovulation, if not then ti could be she didn't take for several days.

Going over 63 days can be OK for medium to large breeds but a no no in many toy breeds, or those who often have more difficulty whelping.

You can have her hormone levels tested at the vets which will indicate whether labour is imminent and they are normal for this stage in her pregnancy.

Is she having an abnormally large or singleton litter that primary inertia could be a problem?

In answer to all of your questions!! Yes she was pre-mate tested!
Puppies arrived safely after a 34 hour labour... she had 15 mins before she was due to go back to the vet for a c-section and she produced her first puppy. We have 2 gorgeous boys!

Puppies were born 3 days late on the 66th day!!

Aww great news.  Went through the same thing with a friend today, his girl was on the same day and is a medium sized dog.