Regarding Form 145 and 146

Based on the facts stated, this appears to be a remittance for advisory services to a UK resident. If the services do not “make available” technical knowledge, skill, experience, know-how or process, and the UK party has furnished TRC, Form 10F and no-PE declaration, the payment may generally be considered not taxable in India under the India–UK DTAA.

In such a case, Form 15CA Part D should generally be filed, as the remittance is not chargeable to tax in India. Form 15CB is normally required only where the remittance is chargeable to tax and the aggregate amount exceeds ₹5 lakh during the financial year.

Therefore, if the non-taxability position is properly supported, 15CA Part D alone should be sufficient. Still, because the amount is GBP 45,000+ and banks often follow conservative internal checks, it is advisable to keep the agreement, invoice, TRC, Form 10F, no-PE declaration, no make-available declaration and CA working note ready. If the bank insists, a CA certificate/clarification may be provided as a practical compliance safeguard.

I have doubt on the wordings part sir 

please kindly clarify it

The conclusion "the payment generally not taxable in india under INDIA and UK DTAA"

Should we take Treaty as basis? Or Indian Income Tac act as basis?