Good luck to all your DC. Just coming back to this thread after having done 11+ for last two years back to back with my 2 DDs.
If anyone wants to ask anything about SPGS, GL, LU, PHS, NHES, LEH, FHS happy to help as we ended up looking at all those schools closely with offers for both DDs.
It’s a horrid process (even worse in 2020!) but they do put it behind them v v quickly & almost everyone finds the right place for themselves.
re: interviews, having listened into them all during lockdown, I can say they are ALL friendly and polite and really trying to understand how your child thinks/forms a view, articulates themselves and is flexible.
HtH