Hi CrispyFB, thanks for your reply. Sorry for taking ages to reply but I was in hospital when you posted :)
I was finally taken in to be induced at 7am on 31 March (after the hospital postponed it a few times as it looked like things might be about to kick off on their own after several uncomfortable sweep attempts), delivered DS at 2am on 1 April (42 weeks exactly).
Things started off well (too well for the midwives' taste, they were expecting me to feel pain sooner with a lower level of Syntocin). However, I just wasn't dilating (and they didn't use Propess as originally planned, went straight to Syntocin).
I still have no idea what actually happened, but they just about managed to break my waters (dilation was still only about 1cm). I can't remember exactly what order things happened in, but something went pop at some point (I wondered if this might be the scar tissue) and I began dilating.
I'm not sure if I had the epidural before this or after; I think afterwards. (Withstood the contractions until the pain made me throw up and I decided pain relief was needed! They don't do gas and air in Spain, just go straight to epidural.)
Baby was on the large side (9lb 9oz) so I also needed an episiotomy (3 stitches). Have a vague memory of the doctor, as she was putting in the stitches, saying there was a lot of blood and she didn't know where it was coming from, but that seemed to have been resolved by the time I was wheeled onto the ward at about 4am.
Later that day, I was still haemorrhaging. Leaving out all the details of the problems we had to finally receive attention and be taken seriously, the hospital put me on the list for a blood transfusion but tried a coagulation agent first, which luckily worked. They were also going to send me for a scan to find out the cause of the problem, but as the bleeding stopped, they didn't do that either.
So, in short, I have no idea what finally happened to the scar tissue and whether that caused the haemorrhage. If not that, I also have no idea what caused the bleeding. I also seem to have a mild bladder prolapse, which may need further treatment.
All in all, not the experience I was hoping for (are they ever?!). And as a result, feel completely yuck about the less-than-pretty changes 'down there' and am concerned about what's actually happened to my cervix...
So I'm sorry I can't offer any words of wisdom to anyone else with the same problem. I don't know if the process would have been any different in a UK hospital (apart from the pain relief, perhaps?), but I suspect they talk through and look at all the options with you. That really didn't happen here, and perhaps I should have spoken out more, but the medical environment is quite different.
That said, the two midwives who were with me for the most hours were absolutely amazing. I can't thank them enough and I thank my lucky stars that I got them rather than some of the others who were on duty afterwards (and who I had the pleasure of for a short time).