Think it must have edged past the seal (or at least part of it - was at a slight angle when it happened) in order for the bit of fluid to leak out. It slipped straight back in though & was only out of place for a fraction of a second.
Would bleeding remove any potential bubbles in the caliper? I think I read about a technique on here where you remove the master cylinder cover, tie the brake lever back & leave it for a few hours for bubbles to migrate to the top of the system. Or it could have been a dream, I'm not 100% sure. Anyone else heard of this?
Yep you heard right, I normally do that trick after my brakes have been bled, it tends to sharpen them up that little bit more, so definitely worth a go. Best to leave it over night though.
If you loosen the MC lid make sure the bike won't get touched and I normally stick loads of rag around it in case of any accidental spillage.
I've been known to leave something on my seat to remind me as well, I'm not a morning person!