No, in thirteen years of operating at LHR I have NEVER seen the ILS for an active runway OTS. All maintenance is done at night, and the active runway is switched for short term failures. LHR has CAT111 no decision on all runways, so there is a lot of redundancy to allow for failures.
Of course, there's be a lot fewer landings at LHR without instrument approaches. SFO in the summer (except for some mornings) is pretty much severe clear all the time.