spray with a good fungicide. I would personally take the outer layer of papery dead leaf off then spray it.
It may be bacterial/viral in which case the fungicide wont make a difference. worth a try though.

It might be Red Blotch - peel off the outer layer/s to see if there's any marks beneath - if its clear beneath, don't worry about it, if there are marks right through, it should be soaked for half an hour in a fungicide like Benlate, but that's been withdrawn. Given the absence of any useful fungicidal treatments on the amateur market these days, the safest thing to do would be to bin the bulb IF the marks go through the bulb tissue.

Thankyou both so much, i have already peeled the outer layer off to reveal nothing underneath, fingers etc crossed hopefully it will be ok. big thanks again. p.