SEN Register: be able to add, edit and delete SEN Types in the same way as you could in the old SEN Manager. At the moment this has to be done via the control panel Global Lists. Increase the SEN Type description from 50 characters to 250, this allows for a more detailed idea for teaches of the SEN Type.
SEN Types can be added within the SEN Register, in the Requirements section, by adding a Requirements record and then selecting '+' next to the Type field. I will investigate the other options you have suggested,