@Beaniebeemer I think there has been clarity that the 'first round' of mortgage holiday won't affect your CS. I'm not aware that they (they being the ratings agencies, Experian and the like) have confirmed that it will or won't affect your CS if you apply for an extension, or apply (for the first time) later in the year, e.g. what happens if you lost your job in March but manage to cling on until October, still no job and you then need a holiday? I agree there needs to be urgent clarity.
But I stand by what I said, even if it doesn't affect your CS please do not do it if you don't need to. It is all to early to say but there's a risk that a bank will decline you (either for a specific rate, or altogether) when you come to remortgage because you have had a holiday. It is a standard pro forma question banks ask. And if you say 'yes, i had a holiday in March - October 2020 because of Covid' from a bank's perspective you are not a particularly attractive loan candidate, because you are telling the bank that you had zero savings and that as soon as COVID hit you were unable to meet your essential expenses.
I know this sounds harsh, but that's not what the banks sign up for when they lend. That is why they want to know all your outgoings and set expenses (childcare, HP, credit cards, life insurance, phones etc) and why they make sure you have plenty left over every month after clearing those expenses and the new mortgage they are about to give you. When people say that, effective March, they had the wolves at the door, they do not appear to be attractive loan candidates.
I am not saying this is 'fair', I'm just trying to explain the bank's perspective and ONCE MORE FOR EVERYONE IN THE BACK, why you shouldn't apply for a mortgage holiday unless you really need one.