I'm being coy as prices aren't allowed. But the higher price you mentioned is almost the price of the light & starter kit - 6 colours + base & top coat, prep products etc. The price of just the light from from Coty (Lena White are no longer) is considerably lower than your post states.
There are frequent offers on the light. Coty have an offer on it currently until the 28th & there are so many people who sell it that at any time you won't have to wait long for a deal such as VAT free - beauty express, sallys & capital all sell the lamp with regular promotions.
I would never buy a light from an unauthorised source. It's a false economy because even if it were genuine if something were ever to go wrong you would have no warranty. They might tell you you do have a warranty but if you purchase from amazon, ebay, kaydee cosmetics you can't register the warranty.
If imported (as most of the cheap deals are on the US version) you would 1. have to pay for international tracked shipping to return were something to go amiss & they were willing to refund 2. Pay import fees to receive if coming from outside Europe. The whole thing is a bad idea.
When I pay 3 figure sums of money I expect an assurance that my purchase will be protected for at least a year & that is what you get when buying through official channels.
It's no use saving £50 only to have it break on you 4 months later, have no recourse & need to buy a new light!
.... I was rushing earlier as had a toddler pulling at my leg, and baby starting to scream so I didn't fully explain myself!! The higher cost I have includes some sort of starter kit. The lamp alone was barely any tenners less and is currently not available to buy on its own.