I can understand the delay in getting your bags to LHR. There is usually a 2-3 day delay due to the time change and we prefer to keep your bags with the carrier you filed your delay bag claim with.

What isn't acceptable is that the contracted delivery service seems to not deliver on weekends. Is that the reason why your bags were not delivered on Sat but would have been on Monday?

May I ask, when you got rerouted SFO-LHR, did the agent ask if you had checked in any bags? At that point, the agent could have attempted to get your bags onto your flight. Not sure if there was enough time as rerouting bags can take up to 2 hours.