I had an accident in February where I hit another car, but it was their fault as they pulled out on me.
I put a claim in, and it was confirmed it was their fault.
Will I lose my no claims for this even though it was proved I wasn't at fault?
No you shouldn't. No claims bonus is awarded for not claiming on your own policy. If it was not your fault - the insurance comapny still act on your behalf but as there is no blame - none of the costs of the repairs etc will be met by your insurance company - so your no claims will be secure.
Do your ins co offer to protect your no claims bonus? - if so ask them as it's definitely worth looking into !
it does affect your policy in the future though, if you were to change companies they ask if you have been in any type of accident in the last 5 yrs,your fault or not and they do take it into consideration.