needn't always be a factor/issue tho...
my husband was living in London, UK when we applied out of Kingston Jamaica... i believe that the commonwealth integration may have actually sped things up for us... it's just a theory I have, but maybe there may have been the potential to leverage existing background checks that were required for him to obtain the UK residency visa, possibly leaving only the delta for a deeper investigation (i.e his time in London)... who knows, but while the quoted "average" or 30-50% procesisng time for our office at time of applying was 9m (80% through time in 17m i believe), our application was thru in just over 4m, so it most certainly did not hold us back... he did have to get UK police checks though (and fingerprints for his Jamaican ones done through scotland yard

)... so the time/effort added for us was on the pre-processing end of things.
of course every case is different.. many factors will be considered when they do their checks.