Help needed for LTCG on property sale

Hi All,

I had a property on lease-hold basis from 1995. In 2003 the same was converted to freehold by just paying registration charges to government.

In Current year I have sold the property for around 24lac

please help me how to calculate LTCG?  which base year to consider?   what will be the initial purchase price as the initial lease rent was just 6k per year?

also please suggest if I can claim LTCG benefits for purchasing a new property if I have already done the same in past