If you're feeling flush, I seem to recall someone on the forum (Grumpy?) speaking highly of Hideout made to measure
http://www.hideout-leather.co.uk/made-to-measure
Nine Lives in Farnborough do leather alterations and repairs - If you find something that
nearly fits they might be able to sort it so that it fits properly. I've a feeling they are either Dainese or Ducati's official repairers.