His comment goes to the heart of what the play is about. Poignant and warm-hearted, it challenges the assumptions we make about growing older. "We often approach old age with certain ideas of what it will mean and what might happen but you get a surprise when you get there because it doesn't match those ideas or expectations at all," says Henwood.
The trio are hesitant to reveal their ages, saying people fixate on that rather than the individual.
"It shouldn't be about someone's age," says Blackburn, "it should be about considering the individual and their particular capabilities. We're living testament to the fact that age is only a number."
They say being in theatre, where there's no retirement age, keeps them youthful and active; so do cryptic crosswords but Henare laments some aren't difficult enough to be truly challenging.
They also agree that being eight years older means having more insight into the characters they're playing.
"I love growing old because things make more sense and you have a far deeper understanding of what life's all about," says Henare. "You look back on your callow youth and think, 'Why did I do that? What was I thinking?' Of course, you can't tell this to people who might be going through a similar experience because it's something that grows over time."
Heroes is Stoppard's adaptation of Gerald Sibleyras' Le Vent des Peupliers for the English stage. It became Heroes because the French title translates to The Wind in the Poplars, a name thought to be too close to Kenneth Grahame's The Wind in the Willows.
Philippe, Henri and Gustave have survived World War I but fear they cannot endure Sister Madeleine, who rules the care home where they are meant to grow old gracefully.
So they spend their days on a quiet terrace, looking out to a stand of poplars and dreaming of escape.
Gustave wants to strike out for Indochina; Henri fancies a simple picnic under the trees. But any sort of breakout will be difficult when one has a gammy leg, the other experiences crippling agoraphobia and the third periodically passes out because of a piece of shrapnel lodged in his brain.
"At what point does someone else say, you can't do this - you can't go on a train or travel now?" says Henwood.
"Usually it's not the individual making the decision but someone else who says, 'These are the rules.' When these men look back at the things they've done and the risks they've taken, it doesn't seem like a frightening prospect to go on a little excursion."
Heroes' storyline is certainly not too outlandish. Last year, aged 89, former Royal Navy sailor Bernard Jordan snuck out of his English rest-home after staff were unable to get him on to an accredited trip to Normandy to commemorate the 70th anniversary of the D-Day landings. He travelled by coach and cross-channel ferry to participate and was treated like an honoured guest by all he met along the way.
What: Heroes
Where and when: Maidment Theatre, September 3-26
