Hi just to ask I've got a bit of a problem with one of my buddy bottle valves, Its a black plastic type and it's trying to get out of the bottle, Its leaking slowly and hopefully the next day or so it should be empty, The valve is no good as it's sticking out of the top of the bottle, The type that is on this one is the one with the 3 grooves, Are they basically straight forward to change and if so what would be the best way to do a replacement, Thanks.