Resale Property Without Building Permission Document But All Other Documents Are

I am planning to buy an independent house in Rajendranagar, Hyderabad, but there is no plan and permission document for this house, as the current owner bought it three years before without the same document. I verified online - EC, property tax are all clear, sale deed document mentioning it as constructed house. applied for LRS before 4-5 months but then there is no progress on it as there is some issue on LRS process in Telangana. The electricity bill is clear. I even applied loan through Bajaj Finance and got the reply that it will be approved but due to plan and permission document is missing, they going to sanction only 60 to 65% of total amount instead of 80% Even checked with HDFC bank, got reply that I will get loan but higher rate of interest. Any advice on purchasing this house. Any other document to be verified. Location is really good. Also, will there be any problem in future applying for BRS of this house?