Release Equity for multiple purposes at remortgage?

JJG1984

Hi,
I have tried researching but I am unable to find the answer I need so hoping someone here could help

5 Year Goal
Remortgage to repay HTB loan
Complete a buy to let purchase 

Im in the fortunate position to save £15,000 per year [£75,000 in 5 years]

What I want to know is there any benefit to over paying the mortgage each year as I would never truly be reducing the term as I intend to draw on the money at a later date

Would I even be in a position at the remortgage to take funds for two purposes; HTB loan and BTL deposit?

Im thinking I need to keep both goals separate 

The only reason why I considered overpaying the mortgage is due to reading articles on this site about if savings are generating less interest than the mortgage then over the mortgage. 

Thank you in advance for any advice

JJG1984

Mortgage is currently £210,000 and I can over pay 10%

1.71% @ 75% LTV 

Thrugelmir

By overpaying the mortgage, this would build equity that would help when the time comes to remortgage and clear the HTB loan.  A lower LTV would result in a lower interest charge on the entire debt. Remember HTB benefits from any appreciation in the value of your property.