Vanguard is a fund manager, so the statement doesn't mean a lot. It's a bit like me saying "I put some money in Barclays", without explaining which account.
An ETF is an exchange traded fund. It's just a type of investment fund, but can hold a huge variety of investments. Yes, they can lose 6% overnight. You can't try to predict the growth of an "ETF" because that could contain any type of investment.
Risk averse tends to mean investing will be trickier. It is higher risk than cash investments.
You can't predict what will happen after Brexit - don't kid yourself that you can, it is a path to bad decision and suffering.
Not a chance. Anybody giving you investment ideas or advice is (probably) lying or themselves clueless. To genuinely recommend investments is a highly regulated industry for a reason.
That said, my only recommendation would be to read Smarter Investing by Tim Hale
http://amzn.eu/d/49dxY0s
If you understand what is going on with investing, you can make more informed decisions. And that also means that you can have a reasonable, informed and meaningful discussion on the matter of investing.