I've never seen a ytravel insurance company care about citizenship, only your place of residence. But insurance form a chinese travel insurance company.
Every single insurer I checked on moneysupermarket.com said you need to live in the UK for at least 6 months in the year in order to qualify.
And World Nomads said they wouldn't insure me against losses in the UK since I'm from the UK :/
A photocopy of your passport in case it's stolen.
All liquids to be in marked 100ml (or less) containers in a small clear bag (there are specific maximum dimensions for the bag too but I forget what they are).