Try
http://www.awrtech.co.uk/g-index.htm and you can probably find what you need here
http://www.awrtech.co.uk/awr_cat.htm .
Hope that helps.
Also - I might be wrong - but isn't the the EQ5 a Vixen GP-DX clone ? you might be able to buy a Vixen MT1 motor (if your gearing is 144:1 , which I understand it is ??) and a modified for ST4 DMD2 , or add a STARBOOK retrofit kit.