It is a fern, Pdp, possibly the Lady Fern but not certain. We get quite a few in our garden which we tollerate whilst they are small but they do need digging out later. The ones growing in the wall of raised beds are most difficult.

I agree, a fern. I call them shuttlecock ferns as it describes the shape of the plant. Bracken grows like one single leaf of this but on a stalk.
If you think what you've got is invasive you definitely don't want bracken - it's much worse! And pops up much faster, all over the shop as it grows from tough, thick roots spreading underground, 6" to some feet down.

Many thanks for your answers. Just needed to know as I fancy buying some ferns for my border and my hubby will complain that I have had him digging them up for years! Now I have got good knowledge that they are not the same :-)

Well you don't need to buy them, just stop digging them up! :-) I like them - easy to grow in shade and with a bit of variation through the seasons.