I had my medical on a Monday morning, having got up at 5am for the first flight down. All morning being prodded and having strobe lights flashed at me, and getting lots of jelly-stuff in my hair (they have showers, but you have to ask). Don't bother wearing a suit, you just look more of a plonker when you run round the building (they made me do it), and anyway they give you a dressing gown to wear.
Ask the Doctor (most of the stuff is done by nurses) to give you a class 2 certificate at the same time, it doesn't cost anything extra, and you get the certificate immediately (you'll need it for going solo) rather than waiting weeks on the post.
On the plus side, the nurses are very very cute (so they should be for £400 / hour).
I cheered myself up in the afternoon by having a couple of hours on a proper simulator, to remind myself of what I was aiming for (not that I'm aiming to fly Tridents, but it's closer than a Cesspit 152).