Phil, It was sad not to see you make it to Lilleshall on Saturday, when we heard you'd packed it was obvious something fairly serious had happened so good to hear it was nothing with any lasting damage and you're ok now.
I'm surprised more hasn't been mentioned on here about salt tablets;
https://www.wiggle.co.uk/saltstick-100-electrolyte-capsulesFrom what i've read they give you everything you need to combat sweat loses in a much more controlled and regulated dose than diluted drinks.
I've come to rely on them now and have stopped having any additives in my bottle, switching to just plain water with has been a revelation.
I used to love the flavoured electrolyte tabs, sugared carb powders and good old fashioned fruit squash, but realised it sometimes tasted too good, and was guzzling gallons of it which could leave me feeling bloated, constantly belching and farting and needing too many piss stops if i wasn't sweating ....amusing when solo riding but uncomfortable in a group !!
I've also changed my bike set up to only a single 1 litre bottle because there's never any issues with not having plain water to rinse myself, wet my cap etc. If i start a ride fully hydrated and guzzle as much fluids as possible at stops then i've found 1 litre on my bike has always been adequate. I also find it easier to rinse bottles and get top-ups if it's just plain water.
Before you go down the route of the changing your long standing bottle routine consider you don't necessarily need to balance your salt losses in your drinks.