Do I need a new chain after 1300 miles (2100 km)? I have a Boardman Airpro and probably need a new chain having done about 1,300 miles (2100 km) with it. 

The bike is used for leisure and commuting and therefore goes through all weathers. I also keep the chain pretty clean and well-oiled.

Do I need a new chain? There are so many different types. Which chains will work?
As a general rule you get about 2000 miles out of a chain, but this depends on the chain, it's maintenance, and the use and storage conditions.

It's not out of line for certain brands of chains to need replacement in 1300 miles, since some are either cheaper (and hence more poorly constructed) or more expensive (and hence lighter, with less "meat").  And the more aggressively you ride the faster the chain will wear.

But the real test to see if a chain should be replaced is "chain stretch", using a chain wear indicator.  Generally a chain should be replaced when "stretch" exceeds 0.75%, as measured by the tool.

(In a pinch you can crudely check a chain by measuring against a ruler.  Links are exactly 1" apart when new, and if 10 links are more than 1/10th inch longer than 10 inches then that's 1% wear.)

One thing you definitely don't want to do is to run a chain beyond the point that it's "too worn" -- this causes damage to your sprockets and can cost you several times the price of a chain.