Child ILR on Old Indian Passport

Hi everyone.
My name is Sony. Me and my wife are on ILR since 05-Aug-2011. We got our elder son's (6 years old, born 23-Dec-2009 in UK) Indian passport from London HCI (expired 20-May-2015) and his ILR visa stamp from Mumbai British Consulate. Even though it is an ILR visa, it still had a valid until date of 20-May-15 same like in passport.

We are currently in Birmingham and I have applied for a renewal of his Indian passport with Indian Consulate over here. Hope to get it soon.

Situation:

Me and my whole family want to travel to India in Aug-16.

• 1. My concern is will the ILR visa on my son’s passport is still valid or is it expired because of the valid until date.
  a. Called up Visa and Immigrations and they confirmed that the visa is still valid.
  
  2. My next concern is when we land back in UK, will the Immigration Officer allow my son to enter UK.
  a. Last 3 times when I travelled back from India, I showed both my old passport with my ILR visa and my new passport and I didn’t face any problem.
  b. But when enquired the same with Visa and Immigrations, they told me it depends on the discretion of the Immigration Official at the Border Control.
  c. They advised me to get a NTL Biometric card instead which will take up to 6 months.

Item 2.c is not feasible because if I didn’t get his passport back on time, then we won’t be able to travel to India.
Can someone please advise me if they have faced a similar situation with their child, or can any Immigration expert please advise me on this. Thanks in advance.

Regards,
Sony Idicula

Once the ILE is activated, the holder may be treated as a returning resident. If 18 is satisfied, then no visa is required under 18A. No need to transfer leave into new passport.