On Monday whilst I was in Nantwich Steve let me know that the paw had started to bleed, I rang the vet and made an appointment for Tuesday. As things didn't go to plan and I had to go back to Nantwich on Tuesday I had to cancel the appointment. Zeus was not lame and there had been no further bleeding so we decided to see how it would go. This morning I thought the nail looked weird again and by this afternoon it had come out completely. There was no blood, no swelling and he doesn't seem bothered by it. I contacted the vet and have been advised if it's not bothering him to leave it alone, so we will.
I'm hopeful it's a one-off, an accident and not a condition that can affect dogs where their nails come out ...(lupoid onychodystrophy)