UK mobile/ internet

I planning on moving into my van full-time in the spring. This coincides with my mobile phone contract ending and I’m wondering what others would consider in my situation. I’m after an iPhone 11 and currently, there are unlimited data deals for £30 a month. I could then link this to my laptop to use the net occasionally. But are there better/cheaper methods of achieving a new phone, plenty of data and a good internet connection? I don’t currently have a mobile dongle etc fitted to the van, but could do so.
Many thanks