I am trying to connect my new Nest Thermostat to:
Potterton Suprima 60 HE - Condensing Central Heating Boiler
(Manual: http://www.potterton.co.uk/docs/101209_Potterton_Suprima_HE_Range_installer_guide.pdf, see page 30 for wiring)
Honeywell ST7100 Control Unit...