Mono-bloc mixer taps?

Hi, I bought a mono-bloc mixer tap for my bath about two weeks ago. I was re-fitting my whole bathroom and it was a nightmare to get my bath/pipework in place as I have a very small bathroom.
Initially the taps worked fine, until today that is. I tried to run a bath tonight and my hot tap will not turn off.
I have isolator valves on my pipework, so I can turn off the hot water but I cannot see any way of getting the hot lever tap hood off, without removing the whole block. This means major work to get under my bath and re-do my pipework again.
Please, please please can anyone tell me how I get the tap hood off without having to remove the block?
My taps are fin shaped and move ninety degrees to turn on/off. I can see no visible screw and they won't pull off so I am stumped. I am dreading having to undo everything so that I can get the block off, so if anyone can help me I would ever so grateful.

bunglesabout

Can only guess without seeing it, but you often have to prise out a plastic piece, or peer through a gap which appears when the tap is at one extreme or another of travel. Can be a tiny allen screw.

Many thanks ChrisR. You are a life saver!
I found the allen screw and was able to get the tap off, so I am immensely grateful. However I am not so happy with the company who sold me the taps, since it appears that the cartridge is damaged and will need replacing.
Thanks once again!

bunglesabout