Owning your own home

If I was in your position I'd pay it off.

Keep credit cards going and your score will be fine

Another vote for pay it off. It's hard to find guaranteed gains and you need a place to live. Well, you don't need one but it's a nice thing to have.

Maybe speak to a mortgage adviser and see about offset mortgages? In the current climate, I would probably pay it off, but if you might need the money, paying off a bunch and having the rest as an offset would allow you to use the excess if required.

What @cjr says.

A flexible offset mortgage is the answer. Take out the maximum you can, then put all your money in the account it offsets against. You’ll pay no interest as you’ve effectively paid it off but will be able to draw money out of the account instantly if you need it to buy a £40k kitchen or a 6 litre car.

Is there any reason to not pay it off completely?

You want a Rolex?

Ultimately, is there anything better you can do with the money? If not, pay it off.

If there is something better you could do with the money, the next question is how confident are you in your ability to earn enough to pay off the mortgage when required.

From a credit risk perspective, paying it off would mean that you were a much safer bet for lenders.

From a credit score perspective, i.e. how much money lenders could make from lending to you, that's a bit more here or there.

Also worth noting that, since 1997, the house price index had gone up by a multiple of 4.5, the FTSE 100 has gone up by 43% (peaking at 49% in 2017), and the FTSE All-Share by 74% (peaking at 175% in 2017).

Of course, you may be a shit-hot active investor, able to pick the top & bottom of the market, and spot unicorns before everyone else. In which case, the crypto markets are waiting, forget the house.