Yeah, EA12s were sought-after radios in the 1960s and have matured nicely into sought-after collector's pieces with prices to match.
As has been said earlier, they were quite competently designed and worked well, provided you could get used to tuning across each band backwards. It's very well worth fixing, and shouldn't be too much bother. Faults are always simple when viewed in retrospect.
Eddystones have one nasty flaw. Their lovely low-geared smooth tuning is usually done with a thin shim disc gripped between sprung cones, giving very high reduction ratio in the first stage of gearing. Any wear in the tuning knob bush and a little movement of the axis of the shaft is equivalent to a significant amount of rotation. Any competent model engineer can make spares, but you need the right size reamer to finish it properly.
When you've got yours going, you might stir me into opening mine
David