Sale agreed Scotland, furloughed.... mortgage holiday?

Malaga20

Hi I am new to the forum and wondered if I can ask a question re mortgage (Santander).  In Scotland and our sale is agreed, not concluded contracts yet though.  To complicate its a separation and the date of entry was meant to be end April, however, that's not going to happen now.  We have been maintaining all household bills which I have been managing but with every month its getting harder.  Now Covid-19 and ex-husband has been furloughed meaning we have a deficit per month to pay bills.  The mortgage has been paid this month (April), next payment is due 1 May.  Because the date of entry is likely to be extended finances are going to get tighter and tighter.  Would it be detrimental to ask Santander for a mortgage holiday (mostly interest only, only part is on repayment) around 20th April maybe by then we'll know what the new entry date is likely to be, or even whether it be May, June, July........

For your info I'm buying a new property and loan papers were issued today, solicitor has a copy and so have i.   

Or should I pay all household bills, then my bills, then ex-husbands in that order? 

Thanks,