UK Blizzard balance, minimum purchase

When buying Blizzard balance from the UK, there is an undocumented minimum of £10. Would it be possible to reduce this to a more useful £5? Failing that, this limit should please be documented in our Blizzard Balance article at https://eu.battle.net/support/en/article/25904

Background: Having traded in all my gold for WoW tokens and converting them to £30 in Blizzard balance, it’s very irritating to find out I can’t add just the last £5 for Shadowlands.

(Aside: a GM told me to post this issue here as they are unable to forward relevant feedback from customer service tickets.
If players have a problem caused by errors or omissions in the articles, there should really be a way for customer service to pass this information directly to people who can actually address the problem.)