I still pronounce Glass as G.L.A.S.S, not Glarse; Grass as G.R.A.S.S, not Grarse, and Laugh as L.A.F.F , not Larf.
We moved down to London when I was five so I have a London accent but say all the above words with the proper north of Watford accent like Andy Farman. Really used to get some strange looks at school and lead to me being asked if I was Scottish, Irish, tyke etc.
I am not ticking any boxes as Southern London makes it sound like I might be from south of the river.