The way we do it is Tan goes onto the bathing platform, I have already dropped the boarding ladder down with a warp coiled up by the ladder from the forward cleat.
As we go into the mooring Tan is ready with the aft rope and I nip down the ladder with the forward warp, after we have slowed down and the Morse control is in neutral.
Single handed the warps tend to be tied together so you can control both ends of the boat.
We only had one tricky moment a couple of years ago when we had to wait a long time for Somerleyton Bridge to open, I had gone down the ladder onto the floating mooring (used for demasting)just before the bridge with a rope, Tan did not manage to platform so we only had one rope onto one of the platform cleats, Tan had to get a longer warp to me so I could pull in the boat, needless to say the tide was against me but in the end we managed to get it done.
We tend to go round in a circle now at that location rather than using the platform.
Regards
Alan