Smoking weed on the Orient Express. Drinking at a brothel in Paris. Tricking the military police in Istanbul. Smuggling a Da Vinci into Paraguay. As travel itineraries go, it’s certainly no Saga break. But then Graham Greene’s Augusta is no ordinary literary aunt. The antidote to Oscar Wilde’s Augusta Bracknell, Greene’s 75-year-old heroine is a lusty free spirit who terrorises Victorian values and turns her nose up at the law.

Say what you will about London theatre during 2015, and by my reckoning it was a pretty fine year, there certainly was a lot of it. I can't recall a year that brought with it a comparable volume of openings, not least during September and December, this year's pre-Christmas slate of major press nights roughly double the same time period in 2014. And as proof that people were actually attending the stuff on offer, empirical evidence as ever was the best guide.

From Singin’ in the Rain and Anything Goes to Hello, Dolly! and Mary Poppins, Olivier Award winner Stephen Mear has done more than any other British choreographer to usher classic musicals into the modern era. But adept as he is at razzle-dazzling ’em, there’s more to Mear, as recent excursions like City of Angels at Donmar Warehouse and Die Fledermaus for the Metropolitan Opera prove.

The mother, so often a sentimental figure in art, can be as tenacious and bold as any animal when protecting her young. Mark Hayhurst's play about Irmgard Litten, mother of Hans, a lawyer who cross-examined Hitler – and won – in 1931, celebrates the single-minded determination of a woman daring to take on Nazi might in the cause of her son. Hans was imprisoned in Sonnenburg "for his own protection" on the night of the Reichstag fire in 1933 and, after spending years in concentration camps, was found hanged in Dachau in 1938.

A champagne cocktail with a hefty dash of bitters, Jonathan Kent’s production of this exquisite Noël Coward comedy of impossible passions is as wince-inducing as it is delightfully effervescent. A hit at Chichester Festival Theatre last autumn, it sees Toby Stephens slip suavely into the role of Elyot Chase opposite a sloe-eyed Anna Chancellor as his ex-wife, Amanda.

Bingo: Scenes of Money and Death is the misleading, jokey title of a play about Shakespeare in his ignoble last years, unable to write further, isolated from his beloved London, and hemmed in by local politics. Shakespeare is invited to become a town councillor! To take sides in a dispute about land enclosures! It’s a cracking re-visioning of the genius whom films and myth have preserved in the aspic of lusty, piratic eloquence.

The phenomenal Eduardo de Filippo has no parallel in British theatre. Cross Olivier with Ayckbourn and you get a national institution who acted in and directed his own plays in his own theatre. Born in 1900, it seems odd that he had to wait until 1977 for his first honorary doctorate, odder that the award came not from his native Naples but from the University of Birmingham.

Halfway through Sean Mathias’s gripping new production of The Syndicate, Ian McKellen’s Don Antonio Barracano reaches for his hat, stick and gloves and heads out through the olive groves to "make [a man] an offer". He looks and sounds like a nice old gent setting out for an afternoon stroll. Unless, of course, you’re passingly acquainted with The Godfather.

Terence Rattigan’s art of concealment is what makes The Deep Blue Sea so rich and true an observation of the way people behave. Being deprived of his concealing mask is the crucial idea of the interesting new play partnering it at Chichester to mark Rattigan's centenary: Nicholas Wright’s Rattigan’s Nijinsky, which incorporates an unproduced Rattigan TV script into a drama of why it was not produced.