I used Lush henna for ages , I had my light near blonde hair (dyed not natural, I'd used Superdrug +highlights for a year or so) cropped then used the Brun.
Lush do 4 shades IIRC -rouge, marron,brun, noir
I started mixing the brun with noir ,( 3:1 then 2:2 ) it went darker like a red setter .
It will oxidise and darken over the next 24-48 hours .
It's one of the nice things with henna that you can mix it.
Also , keeping your head warm (clingfilm and a towel) brings out redder tones.
Beware of anything with indigo and bleached hair , it can go green 
Patch test a strand , you don't need to cut it off , just section a piece , tie with thread, henna and wrap in clingfilm.
No metal- no plastic or pyrex bowl, no foil, plastic spoon.
There are some huge Lush henna threads on here too !