The £25 goodybag isn’t really worth the extra £5 in my opinion. People would be better off getting the £20 goodybag and starting the next one early when data runs out. If you are a heavy data user then the reduced speed would be absolutely infuriating for more than a day or so.
I feel that the £25 goodybag should have a higher data allowance to make it more attractive and better clarity around the throttling after the data is used. And maybe call it something other than ‘always on’ which is too easily confused with ‘unlimited ‘