Regarding the batteries I had what I believed were good silver oxide 394 batteries as they should be but when this new collar came back it didnt like them at all. I'm sticking to rayovac ones from now on.
Should be about £7 posted for 10 from eBay so that will do 5 collars for a season.
Regarding the receiver I have always used Duracell and never had any problems, other than when i forgot to turn it off once and went out with a flat battery :-0