Yes, that's quite pricey! You could get double the SC that for less cost easily, too. Will just miss you, travelling at the same time, but out of LGW (much better F lounge there). Some of our friends will be at LHR though.
I couldn't find anything much better out of Frankfurt (where I'm based). Germany, like the UK, engages in the practice of charging an air departure tax, although it seems like it is the passenger not the airline that in practice pays this (which is not always the case with the UK APD a story for another day). My flight to Inverness was chosen because Inverness does not incur an Air Passenger Duty and it's also a lovely place to go for a hike (I have been told).
Flights to continental Europe on OneWorld carriers were showing around 600 Euros per passenger in business. So the UK or perhaps Ireland is the best option as it was in the 400 Euro range. I was looking to do a quick run (i.e. depart Frankfurt on Friday and get back on Sunday), which I suspect also is why the prices were a bit higher.
A better question, and one which I don't have a great answer for is whether it makes sense to bother with keeping OneWorld status if one is based in continental Europe. There are three carriers in the region: iberia, FinnAir and British Airways which sometimes can limit choices. On the other hand, they are competing against Star Alliance carriers like Lufthansa who have the schedule advantage over them.
In any event, I'm heading back to Canada to visit my family in December during the Christmas break, and found what I think was an excellent fare with American Airlines: €618.78 for an open-jaw Lisbon to Toronto, then returning Toronto to Frankfurt in January. This by the way was ticketed into AA Main Cabin which means I'll earn 70 status credits on that flight plus my partner who is travelling with me will have a checked bag. Interestingly enough, I was able to choose Main Cabin Extra seats for free on these flights for myself and my partner (go figure) including the long haul segments between Europe and America. Yes €618.78 is a bit on the pricey side for travel across the ditch to Canada but considering it is during peak travel season (XMAS) and I'm booking fairly close-in and am getting a Main Cabin ticket, I thought it was reasonable.
As an aside, it seems like booking open jaws with American spanning countries is one way to defeat American giving you Basic Economy options as the cheapest option. Earlier this year I did an open-jaw Toronto to Santiago, then returning Brazil to Toronto and that too only gave me a Main Cabin option for booking.
-RooFlyer88