Yes and they're not very full a lot of the year, either. They nearly always have 7 rows of C. My last flight a couple of weeks ago Was an A320 with about 50% of C and quite a few seats in Y empty. Of course, late April isn't peak season, but it's not the quietest time either.

I don't think anyone's suggesting they're getting these new A/C JUST for prime routes such as LHR (and maybe Germany) but they would make sense as "filler" destinations. Look at TK and how they use their 777/787/A330 etc. on many inter-Europe flights, even as short as IST-ATH. There's no way they'd buy them just for that (or if they did, they'd configure them less premium-heavy) but it increases fleet utilisation with the side effect of letting people know how good the long-haul (hard) product is.

With such a small fleet or A321neoLR I can see A3 trying out 3 or 4 new, long routes with very little risk. They could operate more than that with a lower weekly frequency. They can't fully utilise the fleet because just a single aircraft out for maintenance would mean some flights might not be operated at all. Sending these to LHR or elsewhere as fillers should prove revenue-neutral at worst - so long as they carefully manage how many "cheap" seats are sold and how many upgrades are granted. With the same capacity as an A320 I think they could pop up pretty much anywhere in the network.