I think some sort of approach like some US trading platforms works fairly well. You're asked to disclosed your personal wealth, and only offered say options trading if your wealth is above a certain level. Nothing to stop you lying but that's your responsiblity. So the customer is showing their capacity to handle losses themeselves.
If a bank gives a 30 min sales push of a product, it's very easy for them to give 29mins on the upside with 1m of warnings mixed in. If a customer has been convinced by the spiel and agrees verbally then by the time it comes to signing they're probably feeling committed anyway regardless of the small print.
The bank describing the Cobbett fund as having "greater volatility" is the sort of thing I've heard when having similar products pushed my way. While covering themselves legally it's very unlikely that the customer will understand just how "volatile" these products can be. In my own experience they certainly did not mention similar investments could go to zero with even a modest decline in the underlying assets, something that would have caused a bit more alarm than being told there's greater volatility in these funds.
They show you charts showing what happens when things went well in previous investments, however you get euphemistic terms to cover the downsides. So clear pictures of upside, vague words to show downside.
Betting on black on a roulette wheel also has "greater volatility" than most investment funds. As it turns out these funds were probably closer to betting than investing.
As an investment I don't see them being useful even for people who can absorb the downside risk, you're looking at a range from losing everything to possibly making around 60% pre-tax over 5 years. When I was pushed similar products a few times I wasn't interested, mainly I think because fees and charges seemed to be swallowing huge amounts of the potential returns.