Our lovely vet Peter came over this morning to check her out and agreed that it could have been a wasp sting - apparently, he has seen the same problem recently in a couple of sheep. However, having given Betty a thorough examination (much to her displeasure), he was more concerned that she may be anaemic. He took a quick blood sample and took it back to the surgery to check it out.
A couple of hours later, he called to say that she was indeed seriously anaemic. There is a supplement that we can try but it is important that she is kept as calm as possible and doesn't get stressed by anything. He was chuckling as he advised that Betty now needs to 'live life in the slow lane'. No more excitement for old Betty goat!