Job completed, went well.
Saturday, removed wall unit, hung stand off kit and cored hole. Ran pipes in to loft. Decided to run all of them up as the cylinder was in the loft and the cupboard with the meter was accessible going through the ceiling so made sense. Lost time coreing the hole, think it's time for a better drill mine is on the way out and made it really hard work.
Ran hot and colds to where they needed to be and left them ready to connect Sunday so I could leave the tenant with hot water. 11 hours.
Sunday removed pump and flow and returns in living room, replaced and reconnected with new pipe. Vents fitted in loft. F and R run across loft. Gas pipe renewed and TT. Cylinder drained, H and C connected in loft. Electrics run in mini trunking around kitchen. (Most of the sockets in the flat are surface). Flue out. Timer on. Up and running 9.30 pm. 13 hours.
Back yesterday, flushed, commissioned, removed back boiler, tidied up. Paid. 6 hours.
Cold feed was blocked where I suspected.
Hardest flue hole I've cored yet