mobile antenna

[Midnitemo]

Having just gone legit with my radio's I'm now looking to improve the portable performance further with a new antenna , I have already bought a diamond srh771 for my transceiver which claims a bit of extra gain(upto 2.15 db on 2m)every little helps but I am looking for something a little better specifically to use at work and whilst out camping , it must be compact , easy to deploy , good value and most importantly give me more performance , Harry mentioned a "slim jim" antenna which I really like the look of , it claims upto 6db of gain on 2m , if this is true then that would be a decent improvement but would I be contravening my licence with this boost of erp possibly beyond my allowable 10watt's? I fancy one of the ready made ones from the USA which roll up to store and come with the extra 10/15ft of coax on it(what kind of losses would the extra coax be subject to?) are there any other antenna out there that might fit the bill? my work needs are in the main quick to deploy/break as I'm not really meant to be on the radio as such and it needs to be stowed quick smart if anyone turns up unexpected.