Call either 1900 or 0112689345 and after they answer, dial the extension 4123. More information can be found
in this link. Further, if you don't like to call, you can place an online appointment via Zoom or Phone. Just visit the website and the necessary steps are given there.
Yes, most probably the customs will require you to produce the TRCSL approval. You might also most probably need the Import Control License (ICL). To obtain the ICL, AFAIK, you need to have the TRCSL approval with you.
Here's a link that explains how to get the ICL.
You will need to have the following list of items:
- Application for Custom Clearance of RTTE for Personal Use <== Link
- Seller's Invoice (I think that it's better if the letter is addressed to you and it's better to have the airway bill/tracking number mentioned in the invoice).
- Scanned copies of either Driving License or NIC
- Specifications of the Device
IMEI is not necessarily required.
They will send you a CC email with the required approval. The approval is also sent to the customs and the Department of Imports/Exports. DHL did the clearance on behalf of me and they were happy with the printout of the approval-email.