SR used to do lots of things in those days, which is presumably why LX operates CH-GB now.

If LHR is important to you, fly BA nonstop or LX via ZRH. LX provide a remarkable service from GVA, ZRH and BSL to LCY which suits me and no doubt others.

You mention easyJet in passing. Presumably you won't be using them as they serve a greater variety of LON airports than LX or BA - STN, LGW and LTN - just not LHR.