how to register a loss on an unlisted share with zero proceeds as i get a red message whatever

I have been trying to fill in my capital gains sections for shares. i have one unlisted share that has zero proceeds and i need to register the associated loss. However, on the web site if i leave the disposal proceeds box empty i get a message in red saying i have to fill it in. On the other hand if i put a zero in the box i get a red message saying i can't do this either. Could you tell me how to get through this impasse? Thanks

Hi
You will need to enter the disposal as £1 and then add that again to the loss so that you dont lose out.

Thank you that worked