After 24 hours trying to get an answer out of the Vets, she finally just rang back with the diagnosis that Woofie has a Peri-anal gland adenoma. She indicated that it was cancerous but after asking her straight twice I have still come away unsure. She said it would have been unlikely to have spread and by removing the adenoma with a good margin he would make a full recovery. My usual vet will be ringing me back on Monday to discuss booking Woofalump in for the operation.
I have more questions than answers at the moment as because Woofie is castrated I thought it was very unlikely for him to have this type of lump.
Not looking forward to booking him in for an operaton as he is so fit and well. I hate to put him through the anaesthetic and cause him pain when he is so well

I am going to write down questions to ask the Vet when I speak to him on Monday.