DK32

Wiring a B7G base on a Octal plug only requires bending up the g2, g3 and g4 base pins. The other B7G base pins can solder directly to the top of the Octal plug. The g3 and g3 swap over, g3 by an insulated wire underneath B7G base and g2 past g1 on the outside.

A cap can sit loosely on the B7G tube/valve DK92 top wired to the B7G g4 pin. The assembly could even have a cut down plastic bottle pushed on to give original shape and size.

It seems to work quite well. A similar arrangement could replace a DK1. I will examine later how well a pair of 1j24b rod pentodes work (they do replace DK91 / DK96 (see notes on a single tube version a pair of 1j24b works much better) with one as Triodised oscillator and one as Pentode Mixer).  The 1A7GT seems cheap and common in USA, but maybe x4 more expensive in Europe. Also you may have an alternate Heptode /Octode to hand. The DK1 thought is pretty nearly unobtainable, though a 1A7GT or DK32 with base changed ought to work. I will try DK92 and pair of 1j24b rod pentodes in place of a DK1 later.