Good to know @LG. Do you plant into clay or add grit and things? Do you have any other tulip secrets to share?
I haven't much luck with getting distance out of old tulips. I'm on clay and I suspect they rot in the wet if I plant them into open ground. I planted a load in a new composted raised bed a few years ago and every last one rotted over winter. Some of mine used to come up 'blind' (non-flowering) but I suspect that was because didn't feed them as they were dying back.To get longevity out of older bulbs I hear you should plant them very deep, feed them well and add a load of grit to the soil. I planted some species tulips in 2019 and even these seem to have disappeared.
I have to plant tulips very, very deep because otherwise the squirrels get 'em. I have Apeldoorn and Ancilla which come back better every year, and Queen of the Night which are smaller but keep coming (probably been in 5 years now).
I really rate Lidls and Wilko seeds. Had a few plants from Lidls and they have done well also
Apeldoorn too are keepers - I think I planted 5 bulbs a few years ago:
I've got some hardy 'species' tulips that come back every year in my heavy clay soil. They are only basic simple red ones, but they are a lovely shock of colour in spring!
Just to add as well as my Angelique and various mixtures of tulips have been coming up for 5years + without issue - plant deep and add slow release fertiliser, dead head but let the leaves die back and give them a water with some baby bio.