Well done Nick,
Totally agree with all above. One thing - don't expect previous experience in RNR to help too much. The RAF works in a weird and sometimes wonderful way that is significantly different to the RN and mystified me when I was first exposed to it. Concentrate on one thing at a time -prioritise IOT, worry about engineering later.
As a JEngO you are the link and the buffer between the techies and everyone else, SEngO, Pilots, Navs and adminers. Remember the JEngO's office is a place for having a word with Aircrew as well as lineys. If they are being out of order in the Line Office invite them into the office for a chat. Better that they vent on you in private than on the Sgt in front of the SACs. If there is a problem you can then sort it out and not embarrass anyone.
Happy to download my (recent!) experience (RN and RAF) by PM rather than bore this thread for longer.