Can’t turn TRV valve

The hand-turning valve on our radiator in the bathroom will not turn on. I have been googling around it and it doesn’t seem like the TRV valves most people talk about on forums. I can’t seem to remove it and it’s beside a corner so it’s tough to try to turn with a spanner, can’t get a good swing at it. Any tricks on how to turn one of these when it’s stuck?