The Jet2 engineering department is staying at BOH (for the time being anyway) so the 737 B1 engineers will be based at BOH but no doubt working at LBA or MAN as required. The Ops jobs are all LBA based but while head office is still at BOH, thats where they are interviewing.
The loaders jobs are for work in the old Channel Express hangar loading the air Contractors aircraft (Jersey news papers etc.)
Hope this helps
ILS