Well the evening's tinkering was a success. I replaced two complex transistor comparators with op amps and the used-to-be transistor/resistor only 555 circuit still works. Now minus 14 transistors.
Also taught me how dodgy breadboards can be. It "works"... if I poke things until the LED flashes properly. Think I have lots of flakey connections around the place.
Still it's learning. Fulfils it's purpose.
EDIT: I'm going to give the breadboard(s) a bit of grace here. When I tested the comparators in isolations they were always spot on. The latch was a little flaky. I built it originally using this guide:
http://www.instructables.com/id/Build-Your-Own-555-Timer/I note he takes a short cut on the latch and I confess I didn't look into to it much. He under cut the 555 design by quite a few components. Maybe it's that which causes the circuit to be a bit flaky.
(also this evening I was playing theremin with an LED and an op amp balancing at threshold, all I needed to do was wave my hand within 2 inches of the breadboard and the LED lit, which continues to raise the ponder-ment about building a simple theremin.