I would say that the problem lies with system balancing.
Do any radiators get hot?
Does the system have an external auto bypass? if so adjust to 4.
An easy check to see if it's the controls or the system is to force the boiler into chimney sweep mode. press OK button for 5 seconds. system will then run heating mode on max for up to 20 mins.
Other thing is pump speed may need to be adjusted. default is 3 but may need to be increase to up to a max of 6
the reason the boiler is taking so long to get up to temperature is because the software will only allow a temperature difference between flow and return of around 20 degrees. i'm fairly certain from what you have described is whats's happening. this is normally caused by poor balancing, system flow restrictions, air locks or the boilers own pump not being set to the correct pressure.
The worcester engineer should soon have it solved for you
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