What's the best way to save for a deposit for a flat?

I’m hoping to save £25,000 and will use a help-to-buy Isa – where else should I put my money? Q I have a good credit rating, am disciplined with money and earn £27,000. I am hoping to save about £25,000 to put down as a deposit when I buy a flat costing between £80,000 and £90,000. I will be 48 or 49 when I am ready to buy and would like a mortgage term of 18 years so that it’s paid off just as I retire. (I intend to overpay so hopefully will be pa