Wondering if it’s possible to interline baggage and make a relatively seamless connection between BA and LY or even 6H? The flights in question would be:

LHR-TLV (BA) connecting to TLV-SSH (LY/6H), and back again

I ask because people in the BA forum discussing LGW-SSH route dislike their European business class seating, so it occurred to me that LHR-TLV which has flat bed Club World business class might be a better option.

Of course, ideally this could be constructed as an end-on-end itinerary with two separate fares plated on one ticket. If not, having separate tickets might make rechecking and/or interlining difficult.

On the other hand, perhaps there’s also the option of LY all the way — LHR-TLV-SSH — but I don’t know if LY sell a through-fare LON-SSH? Does it make a difference if the second leg is a Sundor flight or some other low cost brand of Elal?

Clearly this isn’t a common request and it isn’t even possible right now given the situation, but would be interested to find out for future reference…

Definitely a question for BA forum since they're the ones accepting your bags for the first segment. In short, BA will not check you through across separate tickets, not even BA-BA.

Take note that due to the Gaza war TLV-SSH flights on LY/6H are suspended.

Yes, that's clear! I wondered though if anyone has experienced this kind of connection (one airline to another, with both segments plated on the same ticket) at TLV and international-to-international rather than international-to-domestic.

Regarding the through-checking, for the return this would be a relevant question for the LY forum. Namely, would LY at SSH through-check a bag to TLV-LHR on BA or on LY?