Tour operator refusing refunds

[Guest]

Getting married this year and booked a two centre honeymoon with major tour operator. So far have paid £1100 deposit and balance of £5000 due in early May. Due to COVID-19 crisis both destination countries have closed their borders. I see no realistic prospect of holiday going ahead. Tour operator says if I cancel I will lose deposit. They say 7days before departure they will confirm if holiday can proceed. If it can't at that time the will give credit note or allow "free" changing of holiday dates. Booking conditions appear to say that I can cancel without penalty if cancellation is due to airspace closures and major incidents amongst other things. Where do I stand