Many thanks for all the interesting chat this question developed (and some slightly off topic!). Exchange rates are clearly an issue but airlines were getting help on exchange rates then I found this which may explain the recent hike:
http://punchng.com/exchange-rate-for...s-raise-fares/
I looked at Expedia and Opdo and they are indicating about £1700 for my sample flight, which is better then the BA website of about £3000: but still crazy. What is really anoying is that they quote and charge me in USD even though I pay with my UK credit card, on a UK(?) website and with a VPN on giving me a UK IP address - so no reason to convert this to nira in my mind but I guess that is a tax thing.
Anyway there don't seem to be many solution to my problem...except swap to differnet airline. Qatar would still get my points, but rather a long route for a weekend (first object is to get the missing 110points for my gold card). Other airlines would get me home to see my family for longer. Third wait until exchange rate issue re-adjusted before buy more tickets!
Longer term take a single and then start buying UK originated flights...