Ah sassenach, but it's all been said before, and it's so much fun
Southwest Airline pilots are as professional as they come, but they have great uniform sense over holiday season. They greet you at the door wearing silly red noses, flashing lights all over their hats, and ties which really shouldn't be allowed out during daylight hours.
All good fun, but we all know they know their job, and respect for that isn't diminished because they are dressed up in a way some might consider unprofessional. If anything it makes me fly Southwest more.
We had an instructor who started coming to work wearing bars, he got canned. That was in the US though, and more to do with the fact his attitude didn't fit in with what the customer's at that particular flying school wanted. I am sure he would fit in somewhere else, and would make a competent airline pilot too.