I’m using gohenry and have done for a while.
It’s a brilliant service with one downside. Before the downside, the benefits are; it allows a custom card with the name “go[kids name]” printed on the custom-graphic card, easy top-ups, a physical card that your child can use for ATM withdrawals and contactless (or chip & pin purchases), in-app notifications for both parent & child, spending history for both parent & child, extra ‘tasks/jobs’ setup for your child to earn extra money. It is very good.
The downside. It costs £2.99 per month, per account (child) - and that’s if you remember to ensure all ‘outgoings’ to the child are covered by a single top-up at the start of the billing cycle. If you need to top-up during the billing cycle, you’ll be charged an extra 50p per top-up. Not great.
If you feel that you can spend (at least) £2.99 per billing cycle to allow your child to receive their spending money and to receive the benefits detailed above, then it will work for you. It is working for me at this point, but I am actively watching for less expensive alternatives. Cash, like the good old days, springs to mind…