Envelope for surrender of Indian passport

Dear all,

I'm having a little confusion about the envelope required by VFS for Surrender of Indian passport application.

The page https://www.vfsglobal.com/india/uk/Surrender.html (Select tab overview) has following info:

Collection Procedure for Surrender Certificates:

Applicants are required to provide A4 SIZE self-addressed envelope (Special Delivery, Silver, tamper proof envelope only) per application

Note - this does not say hard-back


But the page https://www.vfsglobal.com/india/uk/Surrender.html (Select tab Documents Required)

Collection Procedure for Surrender Certificates:

Applicants are required to provide a hard back A4 SIZE self-addressed envelope (Special Delivery)

Note - Does not say Silver, tamper proof

Royal mail does not sell either of these in A4 size online. The closest match they have is C4 (https://shop.royalmail.com/pack-of-5-c4 ... -envelopes)

I called VFS and they said these would not be accepted as they aren't A4. They also said, we must provide the silver special delivery A4 envelope.
When I mentioned Royal Mail don't do A4, but C4, he said I can opt for their courier service. How is that a good solution I do not get!

I looked up on Amazon and I found this item:

It says A4 in the description, but the size they gave is 230 x 300mm

My closest VFS Center is London Goswel. I would be grateful if people can shed light on the envelope they used for successful surrender passport application.

Please can someone advise where to get the correct envelope for Surrender of Indian Passport application?

Thank you,
Cinna