Pay off Mortgage or Buy % of shared equity?

SapKnight

Hi,

Soon to be buying 1st house, which is on a shared equity scheme.
House is £169,950.
20% - £33990 paid by builder
80% - £135960 paid by us/mortgage
have put down 5% of total price for deposit £8497

The 20% is basically an interest free loan which has to be paid back in 10years time. Paid back at 20% of the market value.

We can buy back portions of this 20% over the next 10years in lumps of over £1,000.

If we sell before 10years we give them 20% of the sale price.

I'm just wondering would it be better to save up and buy back the equity of the house OR to make overpayments on the mortgage?

Any help/advice would be wonderful as I can't figure out what is best to do!:)

SapKnight

forgot to add that this is a new build house.