Hi Liz and Louise

Thanks for your help both of you . I tried a number of things and don't know now which one actually wokred - I suspect it was setting up Garmin Express again even tho' it said my watch was connected. The good news is that my Marathon info has synched with GRG which was my main concern. It picked up one other run as well but not all the missing runs 

Good News!  Do you have dates for the runs you are missing? as I may be able to find them and reprocess them.  I can't guarantee I can though.