From my vast experience as a Dog Walker (6 months now), I recommend the following for the sunny weather:
* Slimline backpack/water bladder carrier
* Bumbag for all those things normally stuffed in the (now discarded) coat pockets
* Water in the car, for me (there is always some for the dogs) as anything other than water means being in and out of the loo all day - something I learned when I was a cabbie!
* Silver screens to put up in car while out of it
* Factor 30 SPF
* Insect repellant
* Carabiners just in case
* Bit of nice lippy
I also recommend NOT throwing a ball (not matter how gently as it WILL bounce and go further than expected) for an enormous and powerful dog while he's on a lead.
That bruise has now developed into something two inches long. Ouch. Idiot!