Applying to GTV and lost NI number?

Hello,

I am in the process of submitting my GTV application - endorsement and all that are done. I am asked whether I have an NI number during the process. I lived in the UK several years ago and I had applied for an NI number, but then I ended up leaving the country before receiving it in the mail, so I suppose it exists, it just has never been "used".

Does anybody have any idea what the best approach is? I was thinking of saying that I do not have an NI number at this stage, and sort all of this out once I am in the UK, unless this may become a problem later on...

Thanks in advance to anybody who may have any ideas!