engine overhaul
On this side of tha atlantic engine overhauls tend to be mor predictable than in the USA due to the certification required to do the job in the first place, however there are company's that have a good reputation and those that don't.
I wont comment on the bad ones here but a bit of asking around the business will find a few answers.
I have found that running the 20% extention is OK as long as you have a good engine but don't go further than that as you are likely to run into problems with re-using the crankshaft due to bearing wear.