Hi Palermo,

yes there is a fast track on arrival at LHR in T3. Sometimes crew forget to hand out passes so make sure you request for you.
Service out of DEL is not as good as ex BOM, but still surpasses BA and is much more customer friendly. Meals are actually plated rather than a single casserole and winelist is often better. The seat is great and they actually carry bedding and a duvet to help you sleep better. Entertainment is more bollywood focussed but no chance of not getting AVOD as all longhaul aircraft are equipped. If you aren't flying on a Tues/Weds you'll have a 77W otherwise a 332. Personally, I prefer the 332 in Business/Premiere in a 1-1-1 layout, as there is no first class so the IFS is in charge of service and the experience is usually very good.
You won't be disappointed. 9W is a little rough around the edges and crew lack the experience of BA, which I find more problematic on a night flight but since DEL-LHR is a day time departure you'll probably enjoy your experience and may even convert to a 9W flyer.... let me know how it goes.