"Mri scan"

My consultant sent me for a Mri scan in May 2016 and I was asked which hospital and I said northern general . My results came back in a week .was sent by my gp on the 1st Aug and I was given the hallamshire but two weeks on and the results are still pending.how come it takes longer at the hallamshire than the northern general.my consultant has also been chasing theses results.i have noticed other people putting comments on about Mri results taking weeks to come back.