Learn British Sign Language online
British Sign is offering an 'Introducing BSL' course which usually costs £25, now on a 'pay what you can' basis. It's an online course you can study in your own time, and you get access to all the materials for an entire year.
The course is made up of 10 lessons, each ending with a short assessment. Once you've completed them all and achieved a passing grade in each, you get a certificate certified by CPD.