the gps locator could be given a miss for most though, unless there is no mobile signal etc, but then if there is no mobile signal then that should have been planned into the risk assessment and suitable measures taken. A climber i know Pete did a course in first aid with lots of severed limbs etc, sounded good, sick of hearing office types on my refreshers moan about tripping over bins and paper cuts. The kit sounds and looks like the proper deal, and could well save some ones life, and considering how harsh the serious injuries incured in tree work are then if not the kit in full...(cotton buds? saw dust in your ears??) but bandages etc, blood stoppers etc should definitely be included in any kit. - you just got to read some of the accidents reported on here to know all of this stuff is good, the kid who gashed his neck in the tree, hell he would be dead if all they had were a few plasters and a triangle bandage, a story where the grounds man went into shock and froze up and was thus useless - perhaps a days training having blood and limbs chucked at him might have prepared him a little, I think the current emergancy first response etc, which appears more to be dealing with your fat office based types dieing of heart attacks from too many mc d's.
Companies should rehearse emergancy rescues - an a company i worked for use to to do this, usally if it looked like we were on for an early finish, the opps manager would come up to the tree and say 'you've just cut your arm, blow on your whistle and after 2 minutes black out' it was a pain in the ass sometimes, but other times it was fun and prepared us for the moments where it was a real situation..... i wonder how many climbers have done a rescue climb since their cs38....... perhaps it should become a requirement to have the rescue climb reviewed every 3 years as well? or even less, make sure climbers are still familiar.