Can any of the FT experts kindly tell me whether using Avios in part payment for a ticket affects future upgrades? I'm thinking of part paying with avios for a LH fare but wondering whether it might have an adverse affect later on. For example, would I still be offered the chance to purchase an upgrade - and even worse, would it rule me out as a candidate for the magic 'ping' at the gate?

No, it should not make any difference, though anecdotally crew seem to feel that pure Avios redemptions seem to get more upgrades than revenue. I've no idea if that is true, but I do know that the underlying ticket structure still makes a part-pay ticket essentially the same as a full revenue ticket and so will be OK for AUP, POUGs (if not too complicated) and involuntary upgrades. It generally isn't a good use of Avios, you would only be getting 0.6 pence per Avios out of it unless there was a special offer on, but if you have no better use for them then it's better than letting them go to waste. There was an excellent offer a few weeks ago of �100 reduction for 5000 Avios, which at 2p per Avios was definitely worth considering. The other catch is if you cancel the ticket, the refund is a bit unclear to me but there were reports of the refund being purely based against the full normal cash price, so you wouldn't get the Avios back, but you would get the same lousy cash exchange rate instead.

You also earn the same TPs and Avios of the full revenue ticket.

A data point from February. I booked a cash fare (�313.42) and reduced the amount with Avios, (5200 avios to save �40), so I paid a net �273.42. I realised it wasn't a great use of avios and cancelled within the 24 hour cooling off period. I was refunded exactly what I paid, the �273.42 and the 5200 avios.

Yes, I think that is what I would expect. The case I recall involved someone cancelling well after 24 hours on the back of a cancellation of a flight by BA. Legally I thought this was dubious, but it may have been a mistake by the agent.