It has never flowered and is always rather scabby.

I'm not sure what it is though the leaves look familiar. It does look very congested though so try splitting it and see if it flowers next year.

An idea - but not sure I want two of them if they're going to look like that... Will have a scape around and see if it's feasible.

Looks like a lilly of some sort. If it is in shade dig it out and place it in full sun then it will get enough energy to produce flowers.

It has been in full sun for several years Loosestrife...

Then I am inclined to think that it is some kind of plantain weed.

Hope not as it was a gift from a Goyer...

Not a plantain, if you mean Plantago species, the leaf is wrong.

I just wish it would flower and settle the matter! Think I'll move it to another place this autumn and give it a final chance.