Thread drift alert! .... the mention of the Strowger Exchange took me back ..... when I worked in telecoms (radio in my case) we often had to work with the Post Office Telephone Engineers (which tells you it was a while ago!!🙂) .... one told me they had a dodge they used to use when they were on call-out ... they used to put a fag paper between two particular contacts at the exchange before leaving ... then at night they'd call a number which would fail due to those contacts not making, initiating a call-out (and the allowance it generated) ... they'd have a snooze for an hour then call another selected number which caused the contacts to open and the fag paper to drop out hence clearing the 'fault' ... all without getting out of bed.
Back on track .... Brough's are obviously not as rare as I thought .... one presumes the prices they fetch reflects the rarity with which they leave collections for the open market rather than absolute numbers?
K