Glad you got the GRD770

, after getting it home let us know how you feel about it.
In general Jessops and other large retailers like Comet etc have poor product knowledge simply because they dont have the time or money to spend on staff training, they should spend money on this but they dont as to most people working in those shops its "just a job" and not a career which requires specialised knowledge of the job hence you get poor product knowledge.
A local specialists camera shop owned by one person or one family will have a lot more knowledge of the products they sell, but unlike Jessops etc prices in specialists camera shops are also a lot higher than in Jessops/comet etc etc.
My local Jessops/comet/currys have been good and get most of the info i want but in other towns its different.