It can be done now, before the sap rises, but the optimum time for Apples and pears is August. That way you do not get the water shoots which grow after pruning at other times.

As above, but expect a lot of "water shoots" during the year which you'll have to cut back

Perhaps make this year the year you bite the bullet and get it trained / manageable size with loss of some fruit this year

For instance, if you are reducing the height, do it a lot with eye to the future, not just back to head height this year

Thanks Owdboggy and Grandad-gar for your helpful answers. I'll be up a ladder as soon as these high winds go away.