Max single trip 35 days vs 36 days needed for cruise?

JJFR

Parents booked on 35 night cruise next year. Sailing at 5pm on first day out of Southampton and disembarking at 6AM on last day back in Southampton, So 35 nights but stretches into 36 days/dates. They holiday a lot so would like annual cover, but can only find policies with max single trip of 35 days. Pre-existing conditions and cruise is to US so Single trip quotes to cover 36 days running into £1000's.
Is it a coincidence that P&O set the cruise time to 35 nights in expectation that their demographic will be covered under their annual policies? If so is the specialist 36 day cover not needed? Would P&O accept the annual cover that contains 35 days max trip length? Or would they insist on 36 days special policy?

IvanOpinion

Find the best quotes you can and then contact the companies directly to see how much to add some additional days. Also, if their house is being left empty for that time, tell them to check their household insurance which may also have a clause about the number of days of being unoccupied.

You could also try asking the question on a cruise specific web site like cruisecritic. Many people there will have been in the same situation.