Can anyone help ID this please?

Can anyone help ID this please?

Observation - Can anyone help ID this please? - UK and Ireland. Description: This was found under mixed woodland in a local park. The cap is around 3-4inches across and clearly wavy rather than round, although this may be due to age/deterioration. The colour is greyish-brown, darkening toward the centre. The gills are free/adnexe

This was found under mixed woodland in a local park. The cap is around 3-4inches across and clearly wavy rather than round, although this may be due to age/deterioration. The colour is greyish-brown, darkening toward the centre.
The gills are free/adnexed - it's hard to tell definitively, and some appear forked to me.
The stipe is fibrillose.
I've been through two guide books for the past hour and can't find anything like it!
Hope someone more experienced can help. Thanks.