Safety Valves, specifically Naylor ones

[BackRoomBoffin]

Hi, I'm plotting a freelance locomotive from a non-existent works.

 

I have become enamoured of the L&Y Jenkins and Yates saddle tanks with their Naylor safety valves and distinctive 3-column arrangement.

 

I gather NER locos also used these for a period, and possibly more, but I guess they may have been hidden behind covers.

 

Is anyone aware if Naylor valves could be plausibly mounted on top of a dome, as Ramsbottom and Salter vales (and other types) were?

 

Also, what is the latest period Naylor valves were used at? The seem to be a mid-Victorian thing.