[MENTION=616]Guinness Boy[/MENTION] @Guinness_BoyIf the boiler does go wrong and let's say you have no hot water, or a leaking boiler, maybe this would be an emergency call out.
If the manufacturer can't come out for the above I don't actually know who is liable for costs, I suppose they can only answer the question.
I have been doing a few urgent jobs since lockdown, only small repairs, and the customers have either gone outside or to another room.
All manufacturers still have breakdown/warranty teams working. Most (Vaillant, Viessmann, Ideal that i know of) are saying dont worry about the annual service too much, we'll let it slide for say 3 months as it stands.
For example, i fitted an Ideal Vogue 3 years ago, and it was due it's 2nd annual service in late March, which i havent done. Cust called me last week about it not working on HW. I went round, immediately diagnosed fault with diverter, called Ideal and they came next day to sort..