[Arran]

Try Mouser or WJOE radios, they seem to carry some obscure bulbs, I got some fuse lamps for my Marrantz from WJOE. One of the common faults these Deforest Crosley's have are the crumbling dial lamp leads, particularly on the one that rotate, that was a popular gimmick even on the later models, my 1938 Brahms model uses something similar even though the dial is rainbow shaped.
Regards
Arran

http://www.wjoe.com/all_lamps.htm