Mumbai Airport

Help on leaving:
Make sure you have the proper means of payment (hotel doesn't seem to like several sorts of debit card - I was OK with a credit card though).
Allow 15 mins or so for check out - if you are leaving at the same time as a bunch of cabin crew (there can be 15-20 on a single 747) it can take a while!
It's only 5 mins to the International airport by hotel car.
You don't need to book the car in advance - just go to the travel desk and say "car for the airport please" and there's usually no more than a couple of minutes' wait.
The driver asks which airline you're flying with: this isn't politeness, there are two entrances and he takes you to the one you need.
At the airport, I got politely accosted by a chap with a trolley asking if I was for Delta airlines (I wasn't), so he ignored me and I headed off dragging both of my trolley suitcases. I wish I'd found a trolley but I somehow forgot to look for it!
To get through the entrance doors into the airport you need to show your ticket or e-ticket confirmation to the security guards.
I was a bit disturbed that BMI wasn't listed on the "airlines from this door" list: but they've only been going to Mumbai for a few months and the sign looks a bit old. Anyway, the driver got it right so trust him.
Inside, follow the crowds. First you have to get your hold baggage x-rayed and sealed (they put a security tape around mine with Air India BOM on it). Then you go and check in.
There was a HUGE queue that the baggage handlers who attached themselves to me (irritatingly) told me was the BMI queue. Having spotted at Edinburgh airport that there was a priority queue for Business and (crucially) Premium Economy customers, I decided to go and investigate this one. So I waltzed confidently past the queue and right up to the front, and lo, there was indeed a priority lane, just for me. Fantastic! This saved at least an hour's worth of queuing.
I checked all the way through to Edinburgh - they forgot to give me my baggage sticker (we were busy discussing if I would be able to make my connection at Heathrow) - but it turned out OK in the end.
I encountered a couple of colleagues who had been in Pune for a tour of duty, who had been waiting in the long queue, and told them to go and queue-jump to the front, for which they were grateful.
If you want to stock up on sweeties or last minute presents, now is the time. Beyond security the shops are more "duty free" type ones and quite expensive. I bought a couple of boxes of Haldiram Indian Sweets, using up the last of my big Rupee notes.
Next step is to go through Border Control. No problems: queue moved efficiently. Remember to keep hold of the immigration form you get on the inbound flight - they take it off you when you leave. Not sure what happens if you lose it but it probably involves paperwork and/or bribery.
Then you settle down in the Departure lounge for a wait. I had a while there: probably an hour or so. There are some comfortable loungers you can lounge on. I kept a look out for Kirsteen and Francis arriving (the arrival corridor is beside the loungers) but the plane arrived at a gate at the other end of the terminal, alas.
After a while they open up the final stage in your progression towards the flight home: the security scanners (hand baggage) for the lounge by the departure gate. This involves scanning your bags and also a full body scan and boarding card check & stamp for everyone. Ladies one way, gents another. They also put a "checked" label on your bags too.
Then more waiting in the final lounge. There was a big screen TV with France v Togo.
When the plane opened for boarding, there was a mass rush for the gate, despite exhortations from the ground staff for everyone to stay seated until it was their turn. Wheelchairs and babies were allowed on first, then they started to board by row number (from the back) but they said that Business and PoshEconomy travellers could board at their leisure so I pushed my way through the crowd. One chap in front of me doing the same fell off-balance as a wheelchair (returning empty) went past, and landed on an English woman who muttered pointedly "I'm Business class too... there's no point pushing" - which I thought was terribly funny - how long exactly had she been in India?! The only thing that works is pushing!
Anyway, another boarding card & passport check and then onto the plane.

And wait.