Spendor CROSSOVER from a Harbeth HL MKII monitor??
The question is copied directly from a current Ebay listing in UK (230480453163). Is that intriguing at all? Probably I haven't studied enough to know such cross-link.
I happened to know that later Chartwell LS3/5A (those with banana speakers jacks instead of screws type) has cross-over made by Rogers (printed on the PC board).