can anyone help. can u tell me if the digi printout in cab is enough or do you need to download on a computer program 
Enough for what?
Are you looking at this from a driver or operators point of view? If it is from a driver’s point of view then you don’t need to do anything as all the info is on the card and it is the responsibility of the operator to download a copy before it gets over written, in much the same way as you hand charts into them after the period you need to carry them has elapsed.
Under normal circumstances a driver is under no obligation to do a printout or download the data to a computer, you only need to do a printout if for any reason you need to add information by writing on the sheet.
It’s the employers duty to keep records and they will need to download the driver card data, or keep a very large box of printouts 
Coffeeholic:
Enough for what?it is the responsibility of the operator to download a copy before it gets over written.
Used my card for the first time a few days ago. The bloke in the office was waiting to lock up on my return and when I offered my card for swiping said he didn’t know how to do that and to bring it in on Monday. I pointed out that I wasn’t on a rota and didn’t know when I’d be back, if ever. He didn’t seem too bothered.
In practice I probably will be back within 28 days and given the rare use of the card it probably won’t get overwitten for a year anyway but I wonder what my obligations are?
In my opinion I’ve presented my card for reading so have fulfilled them. It’s not my fault they were unable or unwilling to do it and It’s a 20 mile commute so if they want me to “drop in” to swipe it they can book me for a shift!