A.  Unlike the earlier Ferrograph tape recorders, the Series 7's used the mini Bulgin 3 pin round  mains lead. The same lead was also utilised on the Hi-Fi amps (F307) etc. and on the later Logic 7 models.

Fortunately, these plugs are available usually described as being for the Quad 33/303 amps. If you need to obtain one of these, then this link to FLASHBACK will  take you to this site.

You can then make up your own mains lead to whatever length you need.

Hope this helps.