Letting cats out after moving house.

[Wholetthetwocatsout]

We moved a week and a half ago and our two cats have been inside - we intend to let them go outside this weekend, when it will have been 2 weeks.
Both cats are outdoor cats and are desperate to go out - they spend a lot of time looking longingly through the patio doors.
They've been fine using litter trays and I will keep the litter trays going in the hope that they will toilet inside.
We've put a cat flap in the back door and both cats have shown interest in it (it's locked).
They are both torties and very feisty - they won't tolerate collars else I'd get trackers for them.
I'd be grateful for advice please - any tips please? (I'd be happy for them to be indoor cats but that means no open windows and risking them making a dash when we open doors...).

Thought I'd update just in case anyone's interested - it's been 5 1/2 weeks since we moved. We found an unfamiliar black cat in the garage so installed a microchip cat flap. The click of the flap as it recognised her chip traumatised our small tortie and she has decided to be an indoor cat. This is fine - we know she's safe and she won't be bringing small creatures into the house! Big tortie is going in and out reasonably regularly but - I think - is spending most of her time inside because it's so wet outside.

I never keep mine in for more than 2 weeks. They are very sensible. They'll explore the garden then gradually further afield.