It is indeed a "jewllery copy"; the design details are much cruder compared with a genuine half sovereign. There are a lot of details missing, such as the "B.P." designer's initials.
They were not faking these coins to try to fool anybody into thinking they had a rare or valuable coin. They were simply putting their gold into a form that was convenient and readily accepted and traded. At the time, both buyer and seller would be aware that the coins were likely to be replicas, it simply didn't matter to them - they were buying and selling the gold, not the coin. And if a foreign tourist came in to buy, then no need to explain to them that the "coins" were not real coins - they were real gold, and that was all that mattered in the deal.
The people who made these coins usually made a slight profit, either by making their coins have slightly less gold in them (21K instead of 22K), or they used 22K gold but made the coins slightly less heavy.
They still make and sell "coins" like these, in the gold market in Dubai. The law in Dubai allows counterfeit/replica gold coins, so long as actual gold is used, and the manufacturer of the replica places a mark of fineness somewhere on the coin. So if you see a small number "21" or "22", written in either Western or Arabic numerals, somewhere on the coin, then it is a modern Dubai replica. If there's no mark, but it's still fake, then it makes it more likely to be an earlier Lebanese copy.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis