end of 2-yr fixed rate - new deal checks?

My 2-yr fixed rate with Halifax will end mid next year. Current LTV is around 80%.

If I decide to stay with them, will they run affordability and credit checks if I switch to a new fix term deal?

Also, how is the LTV determined at that time? Will they be using the property value that shows up in their systems? (I believe they have a price index that their systems calculate...).

Thank you!