Extra 'recommendations' during car service — are they really necessary?

Yesterday I had my Hyundai's 3rd year service and 1st MOT carried out at Halfords. They came back to me with 'recommendations' including: 1. An engine flush 2. An oil flush / fuel system cleaner 3. Air conditioning clean-out (flush?) 4. MOT guarantee (!) 5. Battery change (it's only 3 years, and there's just 11.5K miles on the car!) -- apparently, it's only holding 10.5 volts and it should be 11-12.5 (?) My question is, is any of the above necessary? As I said, I only use the car mostly for local driving and run up about 3.5K each year, I'm a 'light' driver and the car is serviced regularly acc to manufacturers' schedule recommendation. Thanks so much! PS We had to change 3 tyres, too. Went for that or else it wouldn't have passed its MOT, apparently.
1. An engine flush: That's an oil flush prior to the oil change. Too late if the car has already been serviced because it is added to the old oil before it is drained.
2. An oil flush / fuel system cleaner: Might help. Better simply to use decent fuel like Shell V-Power then you never need a fuel system flush.
3. Air conditioning clean-out (flush?): They let off a bomb inside the car, switch to recirculate, close the windows and leave it to decontaminate the ventilation trunking as the engine idles. I reckon you can achieve pretty much the same thing by switching to maximum heat and killing the bacteria that way.
4. MOT guarantee (!): Some kind of insurance that the car will pass its next MoT?
5. Battery change (it's only 3 years, and there's just 11.5K miles on the car!) -- apparently, it's only holding 10.5 volts and it should be 11-12.5 (?): Could be the case because your use of the car has not recharged the battery. But I'd delay until the autumn so you get the benefit of the new battery for the winter when you are most likely to need it.
Answered by Honest John on

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