I feel your pain.
I searched for this same amber reflect-o-lite lens last year. I also found out that the amber lenses are no longer being manufactured.
I was lucky though, after a lot of searching I eventually scored some "New Old Stock" in the UK and I immediately bought the 3 amber lenses they had in stock! Two for the back of the camper and one to tuck away, just in case.
I even posted a thread on it here on irv2 -
Bargman 1400 series (reflect-o-lite) Amber Replacement Lens
My word to you is, if you find some, buy them immediately and squirrel them away!!!
I bought a pair of red lenses from RVplus in the US last year for $8 a piece. I just checked their website and now they're saying the red lenses are discontinued!! AND the back up lights! Darn it!
BARGMAN COMP 34-14-010 - Bargman Taillight DISCONTINUED NO STOCK 1400 Red 34-14-010 - RV Plus
Look up the guy in the UK. He goes by the handle RVspares
on eBay. You might get lucky! http://myworld.ebay.ie/rvspares/
Bargman amber lens part number is 34-14-014
Bargman red lens part number is 34-14-010
Bargman red/white backup lens P/N 34-14-711
I'm glad I bought mine when I did!!