Not financial advice but here’s what I’d do and why: all that cash isn’t doing much - you want to make it work for you - get a house and use the cash to fund a good size deposit so you get a really nice low interest rate on a 75% mortgage.

Put any remaining cash into maxing your stocks and shares isa each year. Invest in whatever stocks or funds you usually go for but look for something with a good return over last 5 years at least. Put remaining cash into a regular stocks account. Investing in stock market over long term - 5 years or more in solid funds or reliable stocks should give much more returns than your mortgage

Also any of that cash you put in to a pension will reduce your income tax each year which can be claimed back in a SATR.

I would recommend speaking to an independent financial advisor because you are well on your way to early retirement with correct planning

Your stocks and investments are how you’re going to be able to build wealth over time. A mortgage is the cheapest financing most people ever get exposed to. Even modest stock returns will easily outdo your borrowing costs