Pay off Mortgage or Offset?

Watty99

Looking for some advice please.
My 5 year fix rate mortgage ends at the end of April 2023

House Value = 280k  Mortgage remaining  115k

I purchased the house on my own - but now my partner has formally moved in a few months ago when she sold her flat.
She is looking to purchase a 50% share in the property to put her name on the title deeds - using some of the proceeds from the sale of her flat.

This mean we have enough to pay off the mortgage now or when the fixed rate period ends in a few months.

SO do we pay off mortgage or use a Offset mortgage to keep the money as a safety net?

How do I add her name to the Title Deeds?
Will she be liable for Stump Duty when she purchases a 50% share now - even though I paid stamp duty myself when I purchased this property at the time?

housebuyer143

Personally, I would offset it fully as it's always useful to have money in the bank.