Tried the donut bottles and didn't really get on with them, a faff to hold and the drink gets warm. I typically use either 500 ml or 750ml bottles with a sports cap and keep the bottle in some sort of waist pack. Will only use these if I'm out for longer than an hour or so. Sports caps can be stiff to open and close and are a pig to clean properly (I tend to soak mine in a Milton solution every few months as it also gets rid of the smell if I've been carrying flavoured drinks). I do have one bottle with a top like this one:
I have a very lovely friend who used to live not too far from Hobbiton who alerted me to the presence of the garden centre and I remembered that UC had a pechant for gardening. I did briefly have an olive tree and a banana (tree,vine?) from said garden centre until I killed them with my incompetence.
I have an absolute blind spot when it comes to gardening, which means in the not too distant future I will need to get the mechanical equivalent of a flamethrower out to stop the back garden doing a fair imitation of the day of the Triffids.