Hi Rohan,
Normally, house banks have 1) bank statement 2) possibility to issue payments and collect cash.
As you mentioned, you are opening up Fixed Deposit account with the same bank/financial institution (i.e. Barclays) as your house bank, whereas, of course, the fixed deposit account does not bear the same service as house banks.
The question is whether your banking/financial institution automatically take funds out of House bank account to be set aside into FD account.
Echoing what Prasad advised, Payment details tab in BP holds the details of bank account you will need to pay into and Payment detail tab in FTR_CREATE transaction is from which house bank via which payment method you would like to pay. Both of them are relevant if you set TBB1 to generate the payment request and F111 to pay. As you know, TRM generates payment request which F111 would process and generate the Payment instruciton file (DME) and sent to bank.
So if your banking/financial institution automatically take funds out of House bank account and you will not need to do F111, I do not think you need to maintain the counter party bank details of your house bank in BP. The payment clearing account in your flow should then be cleared by Bank statement process.
Kind regadrs