PF,
Well done on getting through Selection.
It may be a moot point now given you have decided on the EngO route, but its never too late for a little more 'advice' to give you confidence in your decision.
I would reiterate the points made by Herc-U-Lease, in fact we went through IOT together and are good friends. That said my perspective is a little different as I left the RAF in 2008. My first tour was in a PT, which laid the foundation for my time as an Officer and my current life in the big wide world. I was fortunate to get Sqn tour next and loved it, but to be honest unless you remain in the RAF and are the next Chief of the Air Staff and BAE hand you a position on their Board, you should have an eye on your future. When you leave the RAF as an Officer you are absolutely looked at differently to someone leaving as an Airman, regardless of rank. That is not to belittle anyone, its a fact - especially if you are looking to move into more significant managerial roles outside of the RAF and rightly so. You will be expected to and will have to cope with far more management responsibility as an Officer vice an SNCO.
I would add that if you do get a Sqn tour that does not mean you will be hands on. For the most part you will be dealing with the running of the Sqn - a lot of desk work, personnel issues, Sqn and Station duties, project of many types etc, not the management of the actual engineering issues, or at least that will be limited. Your NCO's and SNCO's are there to manage that as you know and it's a fine line between the EngO who can and does manage to get involved in respect of some of the more complex Engineering issues without his staff feeling like he is trying to micro manage or deal with things they can cope with and the EngO who totally fails in that regard.
Also, had I not opted for the commissioned route I know for a fact financially I would not be in the position I am now in terms of pension as well as income.
The other thing to remember is that life outside of the RAF does not mean an end to the life you know given there is now so much contractorisation of the military. For example there are now 3 companies in North America who operate large fleets of ex-military jets the military contracts for training purposes, one even has an operation in Germany. Canada itself has two major programs, rotary SAR and fast jet training that are civilian maintain, but military operated fleets. The first 3 jobs I had post RAF were actually just like being in the RAF, but without the uniform, one SEngO type role and two that where akin to something like SEngO/OC Eng (if that still exists in the RAF) and all 3 where in Canada or based out of there, not the UK.
Bottom line is I don't regret my decision to get my spine removed and would suggest you have made the right choice too, but make sure you capitalize on it. There is now far more competition for the decent postings and you will be up against some very hungry and capable direct entrants. Enjoy the time you serve, but plan for the future and regardless of what the armchair critics and sheep would have you believe, there is actually a huge choice of work out in the big wide world - as long as you don't just limit yourself to one small part of the UK and have a resume that demonstrates you are capable and have the experience that will get you an interview.
Best of luck fella