Radiator Value cap

Hi. Complete novice when it comes to plumbing. This should be a simple question. I have a radiator which I can only turn on and off with a spanner. I'm sure I can buy a cap for it as I think the valve is a locksheild valve.

Could someone tell me what I need to buy?

I thought something like
https://www.screwfix.com/p/universal-radiator-valve-cap-white/35656
or
https://www.screwfix.com/p/drayton-radiator-valve-cap-white-5-pack/5649r

but I wasnt 100% sure.

Thanks

Here is the valve

1. Each radiator will have two valves.
2. One which can be used to turn the heat up or down:
2a. This will either be a Thermostatic Radiator Valve. Usually quite a large round head with numbers on it, often ranging from 0 to 6. Works automatically in that you set the desired heat, (e.g. 4 for a living room) and the valve closes and turns the radiator off when the air in the room reaches that temperature. Actually closes gradually as the room heats up.
OR
2b. A Wheel Head Valve. Usually a smaller (white) plastic head. No numbers, but usually ridged / knurled, to give a hand grip. You turn it (looking down) clockwise to shut the valve and anti-clockwise to open it. The closer to fully closed the valve is, the less heat the radiator will give off as the flow of hot water through it is reduced.
3. One which is used to control the maximum flow of water through the radiator. This is a lock shield valve. It is normally adjusted using a spanner while the whole system is balanced. It should not then be touched again. They usually have a push on or screw fit cover, but either the cover doesn't turn, or turning it does not affect the valve. The cover is largely decorative.
4. If the valve you are talking about is a lock shield valve, as said above it shouldn't be touched. A suitable cover is Screwfix 35656.
5. If it is a wheel head valve, then Screwfix 83291.
6. Screwfix 5649R is not suitable. It is only used to replace a Drayton TRV when the head is removed, e.g. for decorating.

Thank you. It is the temperature control valve and it's a wheel head valve. My mistake. Screwfix 83291 it is. cheers