How to fix Address list

[DireEmblem]

So, I've been given a list of incomplete UK Addresses, and tasked with finding a way to verify and complete the data.

I've had a quick look online - Royal Mail for example would allow you to run up to 50 requests a day, and more and you hit a paywall.

Any thoughts on other sources. The list is in excel, but I'll happily convert into SQL and write javascript if I can find an alternative source!

 

[DireEmblem]

Thanks all - checked out PAF briefly and it looks pretty decent. I have about 200,000 addresses to parse and check.