How to round up parts of a week to whole weeks

Excel 2010
Happy New Year to all,
I have updated an example page.
I am trying to help a charity who hire out mobility scooters and wheelchairs but I'm having trouble doing it.
They could be hired from as little as one day but could be out for 6 months or a year
They charge a fixed fee of £5 for each week or part of a week, so if it is 7 days (one week) it is £5 and if it is 8 days it is £10
I deduct the start date from the end date which gves the days and then try to convert that to weeks but it isn't working out too well. I would like 9 days for instance to = 1 week 2 days, but I can only get 1.29.
The next problem is getting the weekly (or part weekly) fee of £5 to work. for nine days it should be £10. Is there a way of rounding up the amount of days to make an extra week.

Thank you