1st time homeowner and poster

Bought our first house in Aug '17, not moved in as yet(wife's job commitments) . The house is 2004 build, fitted with boilermate2000(from new??). Possibly ridiculous questions, but i cannot find any similar information in previous posts:
The house(3 bedroom detached) is unoccupied at present, soon after receiving the keys i switched the energy from 'pay as you go top up cards' to credit 'direct debit payment' and had 'smart meters' installed. my daily rate currently while house empty is around £1.50/day and last week when extended family members stayed there(2 adults/ 2 children) was nearer £4/day.
how can i minimise this cost? what settings are most efficient to have the boilermate thermal store/ domestic household boiler at?
i do not wish to risk turning off the unit having read multiple horror stories on this forum that components fail upon restarting. the dropping ambient outside temperatures requires would also agree with leaving minimal heating available.
domestic household boiler should be set to maximum? how should the analogue pin timer be set, to take advantage of off-peak times?
any information or an 'idiots guide' to this system would be very much appreciated.
many thanks, G.

Timer is for heating only

Your GAS boiler needs to be on MAX to satisfy the Thermal store

Anything from 20 to 50 pounds for energy per week is normal these days

Download books user & installer from Gledhill website (free)

Mike
MGC/H2O
Norfolk

thank very much, that is mostly what i had worked out. i also now have the manuals downloaded for future reference.
kind of frustrating permanantly 'storing the heat' at 80deg or whatever it is, especially when the property is vacant. ho hum.
thanks for your help, i'll try and minimize my ignorance...