Germinating seeds HELP

Hello

I have been germinating seeds in soil for a while to decent effect. I live in the UK and have them in a mini box greenhouse in my conservatory.

However, this time 5 out of 8 seeds didn't germinate.

The things I changed from my usual way is as below:

I used multipurpose compost not specialised seedling compost (mistake I know)
Planted them a bit deeper than usual as advised by a friend

My question is this:

With the seeds that haven't germinated can I get them out the soil and try them again in seedling soil and closer to the surface?

Or are they duds now they haven't germinated and useless.....?

Or is there a better way to get these seeds to germinate for me?

Thanks for any help and sorry if basic question

if the seeds haven't cracked you could try, put them between sheets of damp kitchen roll or plain toilet roll then place in a plastic bag so they dont dry out, when the tap root is say 5mm long transplant into unfertilized soil

Dampened paper towels in a plastic bag in a dark warm spot like a cabinet will work very well. If they arent cracked keep trying