Yes, I did wear a suit, and it was probably appropriate for Oxford.
I had about a 45 min interview with a senior FI who was a decent chap, gave him a brief on Ex 6 for 10 mins and then he asked questions on all sorts afterwards (I think we somehow got to mercator charts or something!) and checked log books etc.
Then an interview with the ops manager and HR manager for about an hour which was very relaxed. Just a general chat about my goals in the industry, past training and my availability etc.
All in all it went well, though I have to take a flight test sometime in the next few days for standardisation which is fair enough.
Hope this helps,
RC