I asked this question over on the l "Long distance cycling forum", but maybe some fellow tourists have experinced my problem.

I've increase my mileage quite a bit this year and completed my first 3 centuries over the summer and done a couple of week long tours. I've never suffered from skin rashes or break outs, but I have developed a hard spot on the inner bit of my right buttock, just over my sit bones (FYI I use a Brooks B17). I noticed the area was tender, not really painful, down there so pushed and poked it and (sorry for being explicit) got some watery blood coming out of the tender area into my butt crack.....After about a week it has now almost completely gone.I'm thinking it might be bursitis or "Weavers Bottom", anyone had something similar

Sounds like either a saddle sore, or an abscess.

Bursitis is an internal ailment of the bursa (small "cushions" between bones and tendons).

If this is located directly over the point of pressure this is a decubitis ulcer also known as a pressure sore.
You are going to need to avoid pressure on this area for the time being. This may require you to change saddles as it heals.
I have never experienced this to the extent that you have but I have seen it in others.
And it is rather nasty.

Exactly, its completely internal, no exterior signs at all, that's why I thought it might be bursitis. I'll lay off the bike for a couple of weeks and probably pop along to the doctor it it becomes chronic

Internal?
You may have an ischial rectal abscess.
It is not bursitis.

Could be a pilonidal, could be anything. Post a photo and maybe we can comment!

Otherwise see your GP.

If it was bursitis, pushing it wouldn't make it bleed.