There are good books on investing if interested in doing some reading. The Intelligent Investor by Benjamin Graham, is one.
I found the following guidance by searching on GOOGLE.
Defining your investing risk tolerance involves evaluating both your emotional willingness and financial ability to endure market declines for potential higher returns.
It is determined by assessing your time horizon, financial goals, and personality, generally falling into conservative (low risk), moderate, or aggressive (high risk) categories.
I also searched for the top financial advisors in London. It seems there is no shortage!!
So depending on where you are, you might start your own search.
Many folks go it alone. However, in my experience, a financial advisor has kept me from driving off the road. That said, I agree with the above comment, to be careful who you chose.