DERBYSHIRE YEOMANRY officers cap badge

[badgecollector]

hi all
i have picked up a few really nice officers badges lately and will show them on the forum shortly.
firstly, i have this awesome DERBYSHIRE YEOMANRY officers cap badge.
this is the second one of these i have come across here in australia
couple of questions, what period is it? i know there was "imperial", blank, & laurel on the plinth. but what dates match?
also, any ideas of what they sell for? cant find one on any dealers sites
cheers
bc