Just spoke with BA customer services - and the rep checked with his supervisor. Award bookings made on BA.COM you get back all taxes and all fuel surcharges, less a £25 fee.
Award bookings made on AVIOS.COM - the Fuel Surcharge is NON REFUNDABLE.
I dont know how this can be made into a sticky - but I believe this is a VERY SIGNIFICANT DIFFERENCE between avios and ba - and as switching miles between the 2 is very easy - all bookings should be made on ba.com only.
A Happy and Healthy New Year to all at FT.