I meant to post this earlier, but here is a link to a recent ebay auction of one of the FN EX8 top cover and optic: British Experimental L1A1 Enfield Sniper Scope for EX8 Experimantal Rifle | eBay
Final sale price was $1641 USD, which works out to $2180 CDN. I likely would not have been in the bidding for that one.
I have saved a couple photos of this sight before it disappears from ebay. Note the CR number is on the tube, as opposed to inside the lens as on my Cdn example.