Do you mean for your own benefit or morally for the 'good of the nation'?
There's no need to for your own benefit and the system doesn't require it as you count as having a low income, despite being cash/asset rich.
As for morally, forget it. You pay tax in other ways (council tax, VAT and likely inheritance tax was paid on the money you have and more could be paid from your estate when the time comes).
As for financial advice, that could certainly be a good idea depending on how much you have, but if it's not a significant six figure sum, say above £200k or so, there's a lot you can do yourself for free, eg SIPPs and tracker funds, after keeping a few years expenses in cash or premium bonds so you reduce the risk of needing to access investments when the market is low.
Obviously pay off any debt and your mortgage unless the interest rate is very low, say 1% or less.
If you're allowed to put money into a pension (I think you can, even if it's not earned income) and don't need it until you are over 55, that's a no brainer due to the tax relief although there's an annual limit of £40k.
Another Mumsnetter has previously posted this financial planning flowchart which is really helpful
flowchart.ukpersonal.finance/?_ga=2.226806746.650920660.1626839039-1208181054.1626839039
But if you're talking about hundreds of thousands, it's more likely to be worth paying for professional advice, although I'd still read up on the basics so you understand what they're asking you and have an idea about what your priorities and attitude to risk is.