Here are some links to websites that may be of interest

Postcode data

If this site hasn't met all your postcode needs, here are some others that might help.

ONS postcode data - The Office for National Statistics aggregates OS postcode data and data from other sources and provides it in a variety of formats. The source of the majority of the data here
OS Open Data - Originally I used this for most of the postcode data here, but the ONS data is better now I think. They provide a number of other UK geographical datasets freely available for download (I'm using their road data here).
UK Postal Address Finder- A powerful Access application built on this and other data. There is a free version and a paid for version with even more features.
Postcode data mangler - Tony Wilk has written a useful utility to take the postcode data from this site and do various useful things, primarily to let you manipulate it in Excel without running into its file size limits.
Royal Mail PAF - If you find the postcode data here is not detailed enough for your needs (if you need to get address information for instance), then you probably want to be looking at the Royal Mail's PAF dataset. This generally costs money but is available for free to small charities and micro businesses
Postcode boundary polygons - Open Door Logistics provide free Shapefile polygons defining the boundaries of UK postcode areas, districts and sectors. They also provide software for mapping sales territories
GB Maps - Build a custom postcode map or download one of their standard ones

Other postcode sites

There are lots of sites providing UK postcode data. Here are a couple of them, there are probably more but I got bored looking at sites that are just republishing the ONS postcode data without adding any value

Check My Postcode
Check Postcode

Other data

Some links to other data used on the site

ONS 2011 census data for England and Wales
Scottish 2011 census data
NISRA Northern Irish 2011 census data
Land Registry house price data for England and Wales
Companies House basic company data

My other stuff

My Amazon wish list - Perhaps you've become a multimillionaire thanks to something you found on this site, perhaps you're an internet shopping addict who's run out things to buy for yourself. Whatever the reason, if you'd like to buy me something, here's what I'd like.
Doogal Bell's bloggy thing - My old blog

Links with rewards

These links are for products I use and the links will pay me and sometimes give you some kind of reward if you sign up with them.

Fidelity ISA - Sign up for a Fidelity stocks and shares ISA and we both get a £50 Amazon voucher
Freetrade - Invest commission-free with Freetrade. We both get a free share worth £3-£200 when you sign up.
IONOS - I've been running this website on IONOS servers for years and have never had any issues with them. If you sign up via the link, we both get up to £150
UptimeRobot - If you run a website, this service will keep you informed of any downtime. There's a free service, with more functionality if you pay
Ripple Energy - If you can't install solar panels on your house or don't want the hassle then invest in some renewable energy to reduce your bills. If you sign up via this link, we both get £25
Make My House Green - Install solar panels, you get a £100 discount and I also get £100

People I know

Sweetheart Studio - My other half's family photography business
Jo Campbell personal brand photography - And her headshot, personal brand and commercial photography business
BusinessOptix - My employer, developer of a very simple and intuitive process modelling tool

Other links

X-Genics - Developers of an innovative product to ensure compliance to procedures
Jooble - International job search website used daily by millions of people in 71 countries
DevMap - Instantly Evaluate Property Development Potential in England for Free