How do I bleed this rad/ towel rail?

[Clarabellawilliamson]

Had a smaller version of this Raina ladder radiator/ towel rail installed earlier this year. Put the heating on for an hour today and it only got hot the first few rungs.

Feels like I should try bleeding it before I panic but I can't figure out where the bleed valves are?! Anyone know before I begin prizing the covers off the top?

Helps if I put the picture in!

if its sinilar to mine, on the very top either left or right leg bit, there is probably the turn key bit. or it may have a cap over the top of it up there that u need to pull off first.

Thanks! Found it under a plastic stopper.