I hit another car in a car park in January causing a small dent.
I made my insurer aware and they would tell me anything that happened.
8months later I now have my renewal pack through, ive canceled coz of high premium, and strted with a new company because of that. However I was contacted by my new company saying I have no NCB? I ring the original company and they have processed a claim without telling me. Where do I stand on this? Please help.

You have no standing. You caused damage. Your insurance company does not need your permission to cover the damage.

It would have been nice if they had informed you, but they are under no obligation to do so.

no.its late for claim

Your NCB has gone because you hit someone and they claimed on your insurance, simple.
Whatever makes you think they needed your permission to pay out to a third party for damage you caused?

There is no advice to give, your position is quite clear.

They don't need your permission. However, it is strange that they never took an excess from you. Did you not think, within that 8 month period, to contact your insurer for an update? They can't always be relied upon to keep you in 'the loop'. How much NCB did you have prior to the accident? I'm guessing not much, which has why it has gone down to zero - but worth re checking with your old insurer. There may be a NCB matrix in your old policy document if you still have it.

You hit someone else, and a claim was made against you, why on earth would that need your permission? I'm sorry, you don't have the authority to stop people making claims against you, perhaps you should just learn to drive properly and pay attention in car parks!

I would have thought the most insurance companies would let you know when a claim is processed especially if you lose your NCB because of it, although I do not think their obliged to do so.

You would have only been charged an excess if you claimed for damage to your vehicle.