I'm flying SJC->LHR->ZRH next weekend in CW (on a not fully flexible fare - not entirely sure how to find out booking class) with a return a month or so later ZRH->LHR->SFO.

Due to an unexpected event (a death) I now need to stop off in Edinburgh for a night at the weekend, i.e. do SJC->LHR->EDI ; next day EDI->LHR->ZRH, then still take the return. Optimal flight for SJC->LHR->EDI has a one hour layover, and optimal flight EDI->LHR->ZRH has a 1:40 layover.

The obvious way to do this (hand baggage only) would be to not take the LHR->ZRH segment, and book separately LHR->EDI;EDI->LHR->ZRH. But that won't work because the segment is not the final segment, so I will lose the return to SFO (I think).

I asked BAEC Gold line to reprice the ticket exactly as stated, which means all flights would be protected and I'd feel safe(-ish) with a 1 hr change in T5 SJC->LHR->EDI, but this involves (apparently) contact ticketing who could not do it "real time" (i.e. within the 20 minute phone call) and are going to ring me back on Monday, but I was warned it would be "expensive". I suspect this is because they will end up repricing both transatlantic segments.

Other ideas I've had include:

• Moving just the LHR->ZRH leg to the next day now, and booking a separate LHR->EDI;EDI->LHR return (or perhaps 2 one-ways). The issues with this are that (a) I suspect it will involve the same transatlantic flight repricing, and (b) the ticket won't be protected on either change in LHR, and missing especially the LHR->ZRH leg is going to be expensive.
• (Risky perhaps) As above, but booking LHR->EDI;EDI->LHR return and moving the LHR->ZRH leg in the lounge when I arrive in LHR. This way I'll have flown one segment (but not the entire "outbound") which I think may mean the repricing is more generous - anyone?
• Moving the LHR->ZRH leg to some indeterminate point between this and the return (I'm bound to fly that route before the return), and booking a separate LHR->EDI and EDI->LHR->ZRH (in which case at least the second one is all protected).
• Your idea here ...

Which is likely to be the most cost effective way to do this? The extra return LHR->EDI (in CE) is £536 and given the circumstances I don't mind paying a fair amount more than this, but I don't really want to pay several thousand pounds for the privilege of repricing 2 transatlantic flights.