34 month old - one step forward, two steps back?

[BlurryFace]

Hi.

DS1 is nearly three and I'm really unsure what to do to chivvy him on with his potty training. At first he wouldn't sit on the potty without being fully dressed, so we let him sit on it for 5 minutes a few times a day. When we tried to encourage him to take his nappy off, he would throw an absolute fit (literally from "well done, shall we pull your trousers down?") and after a couple of weeks refused it completely, so it went a way for a few weeks then " came back" a couple of weeks ago.

Now he will sit on the potty a couple of times a day with his nappy off and trousers down in return for a coin in his jar - a couple of times he's done a wee, but that's it. This morning I made a big fuss about his lovely grown up pants and keeping the car on them dry but he just wouldn't sit on the potty every hour or so and weed all over the carpet. He threw the potty over the stairgate and demanded "more bum change, want nappy on instead, all done potty".

I'm getting worried because he's been referred to the subsidised playschool to start in January and I don't know if they'll take a child who refuses the potty/toilet (open day soon, no way of contacting them until I get the letter about it).

Do I just dial it back for a bit and gradually increase the times I try him on the potty?