Where to put money to pay mortgage each year

Ojb

In a 5 year fixed with £148000 mortgage I want to pay of in 5 years.
Already paid 14800 penalty free.
Next year can pay £13320 then in 2021 can pay 11958 etc with a final balance of 87k to clear it at the end of the fix.
I have about 50 k now which covers the next 4 overpayments and want to get the best rate . Mortgage is 2.69%.
My original thoughts are:
13k in instant access to pay Jan 2020 overpayment
11k in 1 year fix to pay Jan 2021 o/p
10k in 2 year fix to pay Jan 2022 o/p
9k in 3 year fix to pay Jan 2023 o/p
7k in 4 year fix
However due to rate being low I was also wondering about P2P or stock market investing?
The closest fixed savings of 5 year fix is 2.6% which is still lower then the mortgage rate.
So should I stick with safe fixed savings accounts to offset the mortgage or take a bit more risk with P2P, or the stock market ( using a vanguard index funds for safety)?

AnotherJoe

If you dont have to pay it back in five years but thats just an aim, you could look at investing but you might need to put it off a few years if that doesn't work out.
When do you retire / reach 55? There's some possibilities there with pension.
There's nothing especially safe about using vanguard index funds.

Ojb

Hi another 18 years until im 55

EthicsGradient

You'd get a little more (while still being as safe as possible) by putting it all in a notice account (which do slightly better than instant access) now, giving the notice for it all to come out in Jan 2020 (or late Dec 2019, to give you time for creating subsequent accounts), and then setting up the 1, 2, 3 and 4 year fixes for the subsequent payments. Or you could look for any 18 month, 30 month etc. fixed rate bonds - these sometimes turn up in the best buy tables and would suit your timetable better (MSE lists a 9 month account, but that'd take you to the end of Jan 2020 even if you're quick now, so I'd guess not suitable )