Remortgage with HTB?

Hi guys,
I have a few questions about my current remortgage situation with Help to buy.
I am currently on 1.49% (repayment of £844) initially 35 year deal with 32 years 11 months left. My rate finishes on 2 may 2020. Santander have offered me a re-mortgage of 1.44% fixed for 2 years with £999 product fee.

I also have a help to buy loan of approx 75k. This will need repaying in the latter half of 2022.

my questions are;
-When remortgaging, do I need to inform the HTB authority?
-Should I contact my mortgage advisor and see if he can offer me better deals?
-If he cannot but asks me or tries to entice me to go with him should I? ( he tried to sell me expensive life insurance and I didnt accept)

The Santander remortgage offer is very attractive. It will be tied down till May 2022 and by then I will have the option of paying off the HTB loan via another re-mortgage. Just wanted to see what people thought.

Thanks.