This is no big deal. Just relax and enjoy making like a real pilot - you can do it. IFR is easy cause they generally look after you good. Make sure you put in the remarks part of the flightplan that you are on a MEIR test - and they may look after you even better.
All the stuff above is good, but for what its worth I will give you the perspective of someone who might blow into TAM once every 5 years.
1. At Mount Sandon can I expect to be handed over to the tower??
Ahhh, beats me - but their gonna hand you over to the tower somewhere - just do as you are told. I would expect "XXX descend to Y thousand, call the TAM tower ****.** at Z miles TAM"
2. When I request airways clearance do I give my inbound radial or only if asked??
If it were me they would get "TAM Tower, XXX, inbound on the RRR radial at Z miles, cleared to Y thousand, request clearance, copied Bravo (or whatever!)
3. Could I expect a clearance like “track direct to the field”??
Yeah, or "track direct TAM VOR or NDB". If it were me, I would probably ask for that anyway and maybe request "sector entry and one holding pattern" to give myself time to slow down, loose a bit of height if necessary and get set up for the Appr.
4. Will the tower step me down from my cruise altitude or will I have to request descent ECT??
Yeah, they should step you down or clear you to the holding alt.
5. At 5 ish NM’s will I then be given a clearance to enter the hold and commence a back track of the localizer and report established???
Whatever! They probably have a std way of handling it - just do what they tell you. "cleared outbound for the Rwy 30R ILS Appr, report commencing reversal turn" ???
6. Once in the missed approach do I have to give a Departure report or will I then be given a clearance to continue the climb to cruise level and track to YPMQ???
Yes, you need to give a departure call. Don't rush it. Get yourself set up in the climb - climb checks done - then give the call. I would expect the tower would give you onwards clearance or pass you back to Centre.
Good luck! Give'm heaps!
Dr 
PS: ...... and let us know how you get on!