Variable interest rate question

Quick question for the mortgage experts out there. If I pre-pay a chunk of my mortgage so that I go from an LTV of <80% to an LTV of <50%, will I get the benefit of the <50% interest rate (or does the bank work it out based on the LTV at the time you took out the mortgage)?

Time you took out mortgage AFAIK, as I haven’t heard of banks switching people to lower rates once they reach a lower LTV by repaying the mortgage.

My understanding is you have to switch provider to get the new lower LTV rate.

Never heard of banks reducing APR based on LTV, but my dad did manage to get AIB to move him to a tracker in the good days based on his lower LTV

Edit: But the ECB rate was 4.25% or 4.5% at the time so they weren’t giving him an overall rate reduction

I believe my brother in law persuaded Ulster Bank to reduce his tracker spread based on LTV (in 07/08 IIRC)

This was a self build on land gifted to him which helped the calculation

Thanks for the replies