Echo previous sentiment re Best of Luck!
Our experience with contractor (still ongoing) has been such that I would definitely go self-build if I was doing it again.
Don't think we got a particularly bad builder but yet I'm deeply involved in build every step of the way and now have personal (and not always good) relationships with most of his suppliers. Builder and engineer disagreeing over everything, necessitating us stepping in to resolve and hopefully prevent price escalation. Knowing nothing about construction, using a contractor was a clear decision for us - but between one crisis and another we've ended up having to learn quite a lot about construction anyway: feel that we might as well have gone self-build. Couldn't have been much slower, either: contractor seems to have plenty of trouble arranging teams to show up and there have been times when site was idle for months (the longest being the wait for hollowcore).
In summary, self-build may be a stress-filled nightmare (I honestly can't comment) but contracting can be too. Consider doing the former, saving the money and rewarding yourself afterwards.
Just my opinion! Hope it goes well whatever you choose.