It's a deal! I'm grand with water myself, our tap water is lovely cos we live right beside a bottled water company and naturally enough they get theirs from the same source as us, lol. I can understand how it bores people though - took me a while to crack on with it. I'm a serious tea/coffee drinker (the former is a given being Irish!), easily 6-8 cups a day if not more, though I do use as little skimmed milk as possible and syn any extra. I've even managed to cut right back on bread, but tea? No chance!
Go with the sugar free cordial, start with say a litre a day over the whole day and see if you can build it up. That's what I did (do) with water and I must say, I do find I feel a thousand times better when well hydrated. I do have my bad days where it's just the tea, though...