Help to Buy Advice

Living in the area known as "London prices without London salary" has made an already difficult time to buy a house even worse but moving on my partner and I (both 25) purchased our first home together. After speaking with many mortgage lenders it seemed that they were only willing to offer anything that could remotely get us anything if we had additional loan from the government.

Due to this we bought a new build for £250K which in fairness is a really good price as it was the first to sell on site, and in 3 months they are already selling for an additional 9K. With this we put down 5% deposit, have a 75% mortgage over 30 years and a 20% help to buy equity loan.

I am trying to get on the ball with this already and conscious that the 5 year interest free period will fly by, so what's my best options as with the house going up in value obviously does the loan amount.

In an ideal world we would remortgage in 5 years but I imagine its not going to be that easy. So what's people advise please

Thanks in advance