Thank you so much ifixit.com! Paid an extortionate £24.99 for a replacement cable on Amazon, then used a Torx 4 to do the necessary, following your superb instructions. Worked a treat and my daughter's Slate7 is now charging. Still cheaper than a new tablet (and I hate throwing things away that are all-but working). If it helps anybody, the packet that my replacement came in had the following part numbers: 749770-001 and 729883-001 (these are HP part numbers).