They only know where you live if you tell them.
The options will vary by company policy and its very likely some will be externally managed. First job is to contact each company provider and ask. As above you can consolidate into one scheme but you should check carefully / get some advice as some schemes are best left alone as changes to the law may mean they provide benefits which cannot be matched today.
FWIW I think your Army pension you should leave (its a government one, you cannot buy that in the open market, relatively generous I imagine vs length of service) and the other firm its worth checking the details but perhaps you just leave that. Having 3 pension schemes isn’t an issue and its better than having it all with one company who then goes bust / messes up the management.