The lower you set it the more economical it will be so try it at 50 for heat and 55 for hot water and see how you get on. Even if it takes a bit longer to heat the house it will use less energy as the boiler will be running in condensing mode for more of the time.
New plans have just been announced by the Government
DON'T assume your landlord covers you
Incl £2ish sun cream & £1.50 disposable BBQs