Do you regularly review costs and interest rates? Getting the best deal can make a huge difference over time.
Even if you are comfortable, it's always worth making sure you're not overpaying for things like broadband and mobile phones, and not paying for loads of subscriptions you don't use.
For your savings, are you getting the best interest rate and using your ISA allowances? At least one of you will be a higher rate tax payer so all interest over £500 a year is taxed at 40% unless it's in an ISA.
It's good that you've decided that you should look at investing. As well as the other resources, the Meaningful Money podcast is excellent for learning about finances. There's a recent series that covered the financial flowchart in detail.
https://meaningfulmoney.tv/category/podcast/season-25-finance-os/
One of the factors to get your head around with investing is risk. I haven't listened to it yet, but I see they have a recent episode called understanding risk, which is probably good for a rookie investor
https://meaningfulmoney.tv/category/podcast/season-25-finance-os/
Back to ISAs, if you haven't used your ISA allowances, you can get £80k in by 6 April (£20k for this tax year and next for both you and your DH) so that's something to look at soon, whether it's in cash or S&S.
For your ISAs, you probably want a global multi asset tracker from a low cost provider like Vanguard - if you do enough reading or listening, you'll find that's what's recommended.
You could also consider overpaying the mortgage, but over time investing is likely to grow faster than the interest rate so it doesn't need to be a priority, especially as you can comfortably repay and have resilience, as shown by having savings and ability to continue to save a healthy amount.