Well, finally put the plane back together. Took my time on it. But THREE times I was interrupted by people coming in to have a chat. I was very careful about what it was I was doing so that I continued where I left off without missing anything. However, where I disappointed myself was being in a rush to do a circuit after starting it and rechecking the oil level. It was getting a little late and I ended up not doing a complete preflight check, it was just luck id even taken the pitot cover off!
I survived, but clearly I wasn't in the right frame of mind to be flying, let alone a flight test. If there was an emergency in that frame of mind, would I have handled it well?
If I get in a similar situation again, I'll be sure to just pack up and come back another day. It's not like there's any schedule to get somewhere.