Hello geordie casper.
I had a lot of this type of stuff for about 9 months after the operation. Sometimes the stuff was clearly blood and other times there were lumps which looked like poo but were probably congealed blood. I used to irrigate the anus because that's what I was doing prior to the op. Now I just get excessive mucus which doesn't bother me so much as the pain. (which, in my case, I am guessing is a prolapse- which is also what was there before).
I did speak to the ostomy nurse about it and looked at the options but none of them sounded satisfactory so I'm still putting up with what I've got.
I think you should speak to someone who knows (or can ascertain) what the problem is so that you can make informed choices as to what to do about it.