At that diameter I would have serious concerns. I've removed the under branches from younger prostrate conifers but you have to do it very carefully so as not to destroy the shape. Even then, eventually, they had to go.

Thanks for confirming our thoughts. It's not too much of a problem where it is, mum has plenty of space (unlike me with my pocket handkerchief). She would just like to regain some of her lawn!

At that diameter I'd remove anyway and start with a nice new wee one - after adding lots of compost to the hole!

So would I but Mum gets rather attached. She doesn't mind giving them a "haircut" but hates to lose any. Anyway, it's something for her to think about. Thanks Moon grower.

Update - Mum has decided to leave well alone and live with it.
Trouble is muggings here has to rest the branches on my back while she rakes underneath! The things we do for our gardens! They're worth it though, I don't really mind, it's only once a year.

Why rake underneath... let everything compost down to feed the soil!

She is in her mid 80's and the garden keeps her active. She looks for work and feels good when she's done a lot of it. A bit of a perfectionist too. Mum gets depressed when she has nothing to do, she can't just sit and enjoy the garden, she has to be doing something to it! Her favourite birthday present from my dad when he was alive was a chainsaw!!
She's less than 5' tall and a workaholic, she puts me to shame! I enjoy just sitting and looking when I can but I enjoy the work when it's needed too.