fix for things multi chained  mappers
fix for things multi chained  mappers

danstaines/ensembl,at7/ensembl,james-monkeyshines/ensembl,at7/ensembl,willmclaren/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,mjg17/ensembl,muffato/ensembl,mjg17/ensembl,willmclaren/ensembl,danstaines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,muffato/ensembl,danstaines/ensembl,muffato/ensembl,muffato/ensembl,mjg17/ensembl,Ensembl/ensembl,mjg17/ensembl,at7/ensembl,Ensembl/ensembl,at7/ensembl