Pavement cyclists beware

If the lights manage traffic coming from a side road from the right as a T junction then straight on would be flawed because a cyclist would be less visible until they had passed the forward most car at the lights. At which point the car coming from the right may have already set a course to swing wide (long HGV for instance), leaving no room for a cyclist to continue onwards. You could expect a cyclist to be sensible and cautious about such a junction but, as always, you have to legislate for the least capable.

Not really - you just allow cyclists to treat it as an uncontrolled junction but with priority to the traffic with the lights. Think of the junctions on Tottenham Court road that everyone RLJs in perfect safety for an example of what I'm thinking about. Obviously, the cyclist can't just blithely ride in front of the turning traffic and expect it to vanish mysteriously, but there's no reason to delay cyclist just because motor vehicles need a bigger gap to merge (which is why the lights are there in the first place).

I take issue a bit with "you have to legislate for the least capable" BTW. "Least capable" is in this instance a near-synonym for "most utterly fuckwitted" and I'd submit that a lot of society's problems are explained precisely by legislating for that group to everyone else's detriment. But then I'm an old-fashioned Liberal - the last one in captivity, I sometimes fear :-(