baxi 105e clicking back on after use?

Have just replaced the diaphram on my boiler (thanks to Iain for instructions). Now only one problem to solve. After drawing water, the boiler click off but after about a minute it will click back on (humming with no lights on)....the temp lights will click on and the boiler will click into c/h mode (rads will heat up even in hot water mode only)....this will continue for about 5 mins.....it will then click back to humming mode and then switch off completely. Have now noticed that if i switch the c/h on manually, the boiler will operate as normal but the pilot light will not come on..........any thoughts?? - thanks