Will PBS dependent's ILR clock resets on 2nd entry clearance application before 1st visa expired?

I think there is no definite list of proofs. Just anything that satisfies case worker that you were in a relationship.

We submitted a snapshot of mails exchanged during this time and my flight tickets to visit my wife and child.

Hope it goes well

@bbreddy,
Thanks for information. Just one more question, is the snapshot of mails is emails or whattsapp chats or phone calls made by main applicant from UK to India?? Is it possible to download whattsapp chat history?

Many thanks
Thippesh

There is no hard and fast rule.

I submitted a print screen of 'search results' of emails exchanged with my wife between 'x' and 'y' dates, when she was away from the UK.

I am not sure about whatsapp history download option, but I think you can submit a screen grab of some of the chat history - just to prove that your relationship is subsisting during this time