Strelitzia reginae

I initially kept my Strelitzia reginae, which I grew from seed, inside the house but it got so big I tried to divide it and lost both halves. Bought a tiny replacement 12 years ago, it is now so big (about 2m) it has been re tubbed twice. Mine has far less leaves than yours on 3 'trunks' but flowers, June, each year. I don't feed it often, but keep it well watered. Because of its size it has had to go into the conservatory, which can go down to 7oC.
As you say patience?

I've potted on a few times when the roots come through Siris and when I water I add baby bio but it still does nothing. Had a bit of a hiccup a few years ago when a starling had come down the chimney and trying to get out of a window, knocked it about badly. Hopefully coming back into it's own. "Patience is a virtue."

Maybe higher potash, less nitrogenous feed would help, or it just needs to be older?

It needs light, and a lot of it. I have one that didn't do anything until it was moved into a sunny spot. Around here, they are starting to flower, now. No one ever feeds them, but it does look big enough to give flowers.

There you are Thorny, advice straight from the Azores. They were indeed magnificent in Madeira.

Not much light in these old cottages so I suppose another with leaves only. I can keep on hoping though. Should I just water without any food do you think? I know some plants thrive on neglect, Aspidistra for example, but I assumed these would need looking after better.
Mind you, in Tenerife when I lived there, they were everywhere, as was Poinsettia along the roadsides as large trees and I shouldn't think they got much food.

Pots will get everything a plant needs leached out, where outside it is a little different. My poinsettia grows about 6 feet every year, so after it looses the red bracts, I cut it way back and ignore it until the following Christmas.

It took about ten years from a gallon can to trunked GBOP that bloomed for me.
It not only takes time,but a huge amount of outdoor sunlight.
Two other ways I'm guessing- somebody gives you a division of a large greenhouse plant. OR- try forcing it to bloom using high middle number fertilizers "guaranteed to make things bloom"..do it all summer. Might work.

Thanks everyone for the advice. I'm going to try tomato fertilizer and see how it goes.