Originally Posted by pandaperth

However purchasing close-in to departure might mean you have problems with availability, especially in economy class and more especially in economy for flights such as SYD-SCL-IPC-SCL for which finding availability is always difficult.

Originally Posted by pandaperth

In your case, to purchase with BA you can simply have your first flight (LHR-HKG) with BA (or you could fly LHR-BKK direct with BA).

Originally Posted by pandaperth

.You don’t say which FF programme you would accrue to. All your flights can be accrued to the one programme, but economy class earning can be quite poor, as low as zero on some flights.

Originally Posted by Unterwegs

You could also use a travel agent to book. There are some pretty experienced agents around. You pay a fee, but booking, changing flights or even the routing is much, much easier that way.
I book everything else myself, buy I find for RTWs the money for the agent is well spent.

Originally Posted by Unterwegs

Personally I would do the trip in Business Class, but then the additional cost is significant. For me it s much easier to get over jetlag when I can lay down and sleep

Originally Posted by pandaperth

Good idea to point out the possibility of adding another trip at the end (which could of course be at the beginning instead)

Using the OP's first itinerary for example:
LHR-xHKG-BKK....BOG-MAD
stopover and return to LON on a separate return ticket
then later
MAD-TLV-LHR

Originally Posted by Gardyloo

- In addition to cheaper or more expensive base prices depending on the country of origin, the choice of issuing carrier and the original departure point can matter a lot. British Airways, for example, adds heavy surcharges and fees to RTW tickets that they issue; the same ticket issued by another airline might have a surprisingly smaller "bottom line." Once you get into the thicket of fare construction and taxes/fees computation, it all goes into a black box at the issuing airline, and - sadly - these computations are neither transparent nor debatable. The Oneworld online tool is notoriously buggy on this front; many people think the tool has given them a good fare but when they go to put in their credit card information it all goes to hell.

Originally Posted by Gardyloo

given you have time to plan and do "what if" thought experiments, why not take the time now to "model" your proposed trip with a couple of major FF schemes. How many Avios and tier points would your itinerary earn if you credited them to BA? How about to Iberia? You can look up the Avios and TP earning tables for both economy (fare code L) and business (D) and see the differential.

Originally Posted by Gardyloo

Especially for residents of the UK, starting somewhere else not only can help with the base price and taxes/fees/surcharges, it can also allow you to start or end using home as a stopover point. For example, the cheapest origin point for business class tickets in Europe is presently Norway; a DONE4 from Oslo has a base price £684 less than one from the UK. And if your first flight was to, say, Helsinki, you could have Finnair issue the ticket and possibly avoid big BA surcharges. You'd have to pay for "positioning" flights but those costs would be far less than the savings on the RTW ticket itself. (FWIW Norway is almost £200 less than Spain or the Euro zone for an LONE4 and almost £500 less than Spain/Euro for DONE4s.)

Originally Posted by Gardyloo

Finally, you could also use your time to see if an RTW ticket makes the most sense in terms of total cost. Look at these FT boards - http://www.flyertalk.com/forum/mileage-run-deals-372/ and http://www.flyertalk.com/forum/premium-fare-deals-740/ where members post alerts on good deals.