Alan Ayckbourn is a consummate constructor of entertaining (and sneakily instructive) dramas: setting up a situation, getting all its cogs turning, before dropping a spanner into the works then charting the chaos that follows. He has had plenty of practice. Welcome to the Family is his 88th play – an 89th, already written, is to have its premiere in Scarborough this autumn. What makes him a genius playwright, though, is his skill in crafting clever plots that also pack a powerful emotional punch.