After some fun and games fathoming out how the kitchen lights had been wired, I now have four 4w cool white LED lamps working, fed from one 26w driver transformer.
It turns out that the supply mains went to one of the lamps, and from there broke off as two spurs, each spur feeding two more lamps as a daisy chain. It soon became aparent that i could reuse the wiring.
I had hoped to pull the feed to the lamp over the door (the one without a LED lamp yet) and keep that one as halogen for the time being, but it proved impossible to pull the cable, likewise there was no way to feed a temporary mains supply. So, that one is also wired for LED, and is awaiting a lamp.
A check of the energy monitor, showed that the lamps are taking the expected 16w. This will be 20w with the fith bulb installed. Thats quite a saving from the 250w the halogens took. With all the halogens converted to LED throughout the house, the consumption will go down from 550w to a meer 44w. And the MTF (mean time to failure) for the LEDs is quoted as 50,000h, against the 5,000h for the halogens. At £8.50 a throw, theyre not cheap, but at about £1.30 each, and needing ten to last the same lifetime, the halogens come out at £13! Assuming the lamps last as quoted, thats about £50 saving in lamps alone, and roughly £60 a year in electricity. It also means that if they all last their lifetime, i shouldnt need to change them for about 27 years!