OK so I have a main box and 2 multiroom boxes - all Sky+ HD

Would sky let me keep 1 of these as it is and upgrade the other 2 to Sky Q?

edit: found my answer on FAQ:

Can I keep my existing Sky+ HD subscription as well as my new Sky Q setup?
  • As Sky+HD and Sky Q are two separate services, they require different technology to be used at the satellite dish. As part of your upgrade to Sky Q, we will change one of the elements of the customer's satellite dish such that it will work for Sky Q, but it will no longer work for Sky+HD. In most cases your dish itself and existing cabling will not need to be replaced.

lol oh well