Trying to book a RTW trip for January 26 and seem to be running into a few road blocks, we want to include a lap infant so know this will have to be done as a phone booking.

1) Do BA at any time have a UK based call centre anymore or is it always transferred direct to India?
2) If not I hear better things about the AA phone line, if we book with them can we still get avios and tier points to our BA accounts?
3) When trying to plan a business class routing from Oslo there is essentially no availability (surprise surprise!) but it does show a routing to Perth via Heathrow and Doha but with only economy availability on the Heathrow to Doha leg. If doing the same trip starting in Manchester it will allow the same flight in business but as UK origin is nearly 50% more expensive. What is even more bizarre is that if I switch to asking for a First ticket there is no first options but it does then show up a route via Heathrow with all business availability. Is this a bug with the planner and would fall down when trying to book over the phone? When planning with first and not using any non-business flights it shows up the pricing as the business price still.
4) Final query - If using a city as a forced transfer (Perth to Tokyo via Singapore but as two seperate legs) will this mean that bags need collecting in singapore and re-checking in?

Thanks in advance