Update

The first flowers...

Progress

This plant has spent about 15 years outdoors in my garden. it has been unprotected and is unmarked.

The largest of the Kew collection of agave albopilosa appears to be preparing to flower

These plants are growing just south of London, near Epsom.

This is my ovatifolia. About 16 years old, never had any winter protection.
Agave bracteosa also thrives in an English winter.

My potted specimen is making fair progress in my conservatory, it's winter home.

Bought this specimen at Big Plants a few years back and noticed recently it was beginning to flower.
Interestingly enough one of the two plants at Kew has also recently started to flower.

Try this:
https://www.thegardensuperstore.co.uk/p ... 0FZoHnQdkp