Ghost heating?

Potterton neata heat 16-22 Mark 2 F about 18 yrs old but still going strong serviced every year.
Problem two rads, one in shower room where the airing cupboard is and the other in the bathroom and both were hot this morning yet the central heating has been turned off at the timer control panel.
I note there are two white boxes in the pipe work in airing cupboard could it have something to do with these. Diverter/ Motorised valves I think they are called.

I am covered by British gas but think they may charge if they find nothing wrong.
They keep telling me on each annual visit that the boiler is old and not efficient, but I can't afford their price to change it standard, not to combi, but to a Worceter Green, nearly £4,000 less the 'carrot dangling ' discounts and six items appearing free on quote marked £0 until I queeried the installation of £1500 for two days work and was told the items marked £0 cost was in the installation charge, and I queeried there price for the boiler of £1200 or there abouts. Seems a lot for a standard boiler easy access not struggling in a cupboard and for 1.5 to 2 days as told. Oh! and extra £150 for signing at 'Point of sale' day of survey....
Many thanks in anticipation.

Bob
May 2009