There's a couple of things in here. Firstly, and it's not going to help with the answer but for reference, the package change is completely separate from your choice to convert from TiVo/V6 (the V-HD recording box has been obsolete for many years now) to 360 - although many people do both things at the same time.
As an answer - no. Anyone who converts from V6 > 360 is only doing a software install and will retain the hard drive storage. In any other scenario - so new installs, or conversions from TiVo - the 360-platform only supports one master recording box.
Any additional multiroom boxes on TV360 are then minis without hard drives, this is by design. You can set & watch recordings on the mini, but you are muiltiroom streaming from the master which holds all the storage.
Incidentally, was it a V-HD box that your in-laws had? Or was it a TiVo? There's pictures of the TiVo here & the V-box here - it's too late now, but if your in-law had a TiVo box they could have upgraded it to a V6 and it would have retained the hard drive. Both their (presumably) V6 would then have retained hard drive storage had they chose separately, to convert to 360.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks