US Dollars to put in my bank account

[sc0ttie]

With a large amount you might get asked to prove your identity and asked how you came by it (anti money laundering checks). When you change it take your passport with you.

I wasn't and since you can bring 10k into the country without checks I can't see why the post office would ask me where I got the money, it's not their business how I make my money. I exchanged it today, got £1240 for it in the post office and paid that straight into my bank account.