@dekalbda Ah, I see! I'd thought you were looking at an excellent offer for SIM Only contracts which expires on 9th May.
The offer you mention is a "bridging" situation, as there is a change of rules in June about "roaming" within Europe. As from 11th June, it will be possible to use the minutes, texts and data allowances within a Big Value Bundle anywhere within the inclusive roaming zone without incurring an additional charge. Effectively, any additional benefit from taking up the offer would only apply if your son were to travel outside the UK, and only until 13th July at the very latest, so I'd reckon that any benefit would almost certainly be offset by the additional cost of starting the plan early.
This is a situation which has been developing over the last couple of years, as the EU has required its member countries to move to roaming within the EU without additional charges - see this for Vodafone's new rules. Inevitably it has proved rather complicated, but it probably looks quite incomprehensible when viewed from the outside! Here in the UK we will just about have got the hang of the new arrangements by the time we withdraw from the EU - but we had better not get involved in the politics of that on this Forum.
