Originally Posted by
S_W_S
BA will check through on any connection upto 23:59 hours on the same ticket usually, but with an overnight you can request it back in London, otherwise it'll go into the bag store overnight.
Indeed.
I would ask the BA agent at the starting point just to tag to LHR rather than the final destination. It's within the rules as its an overnight and should generate no pushback.
Having the bag tagged through to XXX and asking for it back at LHR could mean a long wait at LHR for it to be retreived as it won't be a priority to be dealt with.