Where to hold deposit money until completion?

I have 90k in my current account that I’ll be using for a house deposit in 2-3 months time. I’m confused about where is the best place to store the cash until then.

I have an instant access savings ISA with a good interest rate but I understand there’s a limit on how much you can put in ISAs (85k).

Would the smartest thing be to top my Cash ISA up to 85k and then to store the rest in the highest interest rate instant access bank account that I can find?