I spoke to Pearson about the extra voucher but they wouldn't take it as there's nothing in it for them. It's a gift rather than being part of the scheme as such as you don't pay it back. This means that an LBS can't claim back the money for that part. I agree with what you say about being able to source stuff cheaper elsewhere but it's a free voucher so it's still £50 (or £75 in your case) that you wouldn't otherwise have.