If you turn down the valve at the other end, it will reduce flow through the radiator and noise will probably stop. The other valve might have a knob, but more likely a plastic cap retained by a small screw. You take the cap off, and use a very small spanner to wind the spindle down until fully closed, then open it one turn only. Go away for half an hour, then feel the two pipes. Is one of them hot? If not open it another half turn and check again in half an hour more.
One of the pipes is supposed to be noticably less hot than the other. If both of them are fully hot, close down the lockshield some more.
Your valve is a Pegler Bulldog, which is a good quality make. IIRC they are bidirectional, but look on their website for the installation instructions.
The side that heats up first is the Flow side, the other is the Return side. That just means the side where the got water runs into, and out of, the radiator.
TRVs can be noisy when they reach the pre-set temperature and they are nearly closed, when the water is squirting though the almost closed gap. That's why changing the setting a bit will temporarily stop the noise. The arrow shows the correct direction of flow for quiet operation.
Reducing the rate of the flow with the lockshield is correct, and should stop the noise.
If another radiator becomes noisy, turn that down too. Lockshields are not supposed to be fully open, they should all be nearly closed.