They look like crocosmias.
Those are corms rather than bulbs. A new corm (sometimes more than one) forms on top of the old one each year.
More info here https://www.ashridgetrees.co.uk/blog/the-difference-between-bulbs-and-corms/
Yours might be crocosmias
Wow. Every day's a learning day in the garden (especially when you don't know much!). Thank you. They're under two Apple tress surrounded by a raised concrete bed (a very 1960s house!) so should be safe.
The corms shewn were definitely Crocosmia they have spiked leaves with orange flowers something like a gladiolus but they can be a overwhelming and need an annual thinning.