Folks,
Similar to the previous post, plenty of solid advice on the thread but reassurance sought nonetheless.

Arriving at DEL from NRT on JL749 at 16:45 and departing on BA142 to LHR at 01:50 the next morning.
I’m travelling on separate PNRs with no checked bags. JAL have been made aware of the onward flight to LHR as my final destination.
Am I correct in thinking that I cango through international transit and not have to exit through immigration and come back in?
Thanks in advance.