We mostly get Fiesta vans, however, as Ford no longer make the Fiesta van, some new drivers have got Peugeot Partners or equivalents. The vans are for business use only though so no personal use.
Saturdays/Sundays are a regular part of the working week and so if you're not on RD, you can expect to be working those days. On occasions, you may get an 'Additional Rest Day' if there's no work for you, although you can only get a maximum of 2 in a 4 week period.
Rest days are paid at time and a quarter. No extra for doing overtime.
As for lodging, it's difficult to say, some drivers lodge more than others depending on where you are based in the country. You need to be ok with lodging though as it is a part of the job.
It's a 35 hour week which averages at 7 hours per day. You'll likely work more than this though unless you specifically state no rest days and no more than basic hours. Generally unless you're RD, you'll be rostered to do something, even if it's only route refreshing/learning as the job requires you have a sizeable route card.