I've maybe said these things before but it wasn't on this thread and I've changed my ideas over time so I put these thoughts out there in case they at least help develop some thoughts -
immediate cash - 1 months' debts (utility bills, council tax, loan repayments): bank current account will do, doesn't need to earn interest, accessibility is key
back-up cash - Premium Bonds
speculation - trading account: must-have feature is ability to profit from assets with falling prices: account should stay at zero until a consistent strategy has been identified and demo traded
investment - two only are worthwhile -
1) your main residence: because you need to live somewhere and the UK rental market is short-term, insecure and poor value
2) blue chip equity shares for dividend income: buy these and never sell: re-invest as much of the dividend income as possible: put the shares in your will for your children (as long as they promise solemnly to do the same)
Never-ever investments -
financial products, classic cars/art/antiques/wine/first editions, crypto, start-ups, bullion, safe havens.