Grob Queen
Firstly its not R/T its RTF (despite what any instructor or ATCO may say)
In answer to your questions:
1. As a Student/PPL holder you will only be looking at Class G or D airspace and you should be operating in accordance with VFR. Consequently UK procedures require that you are not separated from any other traffic. However in Class G airspace if you are in receipt of a De-confliction Service, ATC will attempt to separate you from all other radar conacts visible to them on radar. In Class D airspace you technically are not separated but ATC will (partially to lessen their workload) often provide instructions which will separate you from other (particularly IFR) traffic. Separation may be provided by specification of a route/heading/altitude to fly at. You must remain in VMC at all times, tell ATC if you will at any time be unable to maintain VMC.
2. Air/Ground can only give information. Aerodrome Flight Information Service (AFIS) normally give instructions to aircraft on aprons and taxiways, once you are on the runway and airborne it is an information service. However, an increasing number of AFIS Units are continuing to give instructions to aircraft on the runway up to the point that they are ready for take-off. This often happens when you need to enter a runway and backtrack to the take-off position. Non aerodrome based FIS Units (eg London Information) give information only. Caution, all FIS Units can relay clearances and instructions but must prefix each by specifying the origin of the clearance/instruction, eamples "London Control clears......" or "Message from the aerodrome authority......"
3. If the unit is suffixed Ground/Tower/Approach/Radar/Control and you are on the ground at their airport, within their ATZ or Control Zone/Area you should comply with their instructions. However, if airborne and an instruction would preclude you from maitaining VMC or you consider it beyond your skill level, tell ATC and specify why you cannot comply.
4. If you end up inside a Danger Area, you must comply with any instructions given by the operator, which will normally be to leave!
5. Mostly correct, but if you intend to fly through someone's ATZ you must contact the A/G or AFIS Unit for it and obtain safety information (Rules of Air Rule 45) or if the ATZ is controlled by an ATC Unit (civil and military), obtain approval to fly through it. If you intend flying through a MATZ it is good practice to contact the controlling unit.
6. Class D, yes, contact and comply with instructions (remaining in VMC).
Hope it makes sense, any queries please PM me.