Having previously worked in D&D, I'd suggest the following.
Beatnik's offering is the pick of the bunch, although ATCO Fred's suggestion of the pause, having said PAN PAN PAN [c/s] PAN, is a very good idea. The ATCOs will end up missing things if you splurge it all out in a one-er.
I would not suggest activating your ELT. If you're high enough to talk to D&D they can auto-triangulate your position +/- a few miles instantly. An ELT may confuse the issue at the ARCC who would detect it's transmissions through SARSAT/COSPAS and could potentially block 121.5MHz also, causing you problems in speaking to London Centre.
Yes the order is not that important, especially in the example offerred when you'd be making git up on the hoof anyway; however, the "order" ensures that you give all the info and don't have to be asked multiple questions afterwards to get the rest of the info. Other info like POB and endurance remaining are fairly essential, although I wouldn't worry about the latter with an engine failure in a single-engine
