Hey.
Sounds like it's going to be a great time!
You can use up to 12GB of your allowance while there. Anything beyond that will start to incur a surcharge.
Most plans now have a charge of £2 per day for unlocking access to your allowances, some older plans don't have that. (If they were taken before the 1st of October 2021).
You don't need to buy the passes, however they do work out cheaper than paying for the £2 daily charge. They are also handy as once you buy them, you can have a £0 spend limit set on the account, and this means you can use allowance without having to worry about accidental spending.
The Go Roam Pass doesn't give you any allowances, it just unlocks access to your existing allowances without you having to pay the previously mentioned £2 daily charge.
Pete.
Mod tip! The author of a post can hit 'Accept as Solution', to highlight a reply that helped solved their query.
