Hi Chrispyduck
The Ketron SD3 is your best choice - read the write up on Jazzhooves
Good sounds and styles and the brilliant PROGRAM mode lets you layer 4 sounds together.

I have been using a Solton/Ketron MS40 module for many years and the strings,
in particular, are still better than those on any modern keyboard today.

There's just one major drawback - no USB socket so you can't use a pen drive etc.
This ties you to floppy disks unless you take up the very expensive (£250 sterling) Hard Drive option.

Best wishes, Tony, SHEFFIELD