I would imagine it's because Sky no longer provide engineer support for Sky+ equipment.
If your new property already has a dish you could connect your Sky+ box yourself and that may be all that's necessary.
If you can't get a satellite signal from an existing dish, or if there's no dish installed you would need to get a local satellite installer to sort it out.
Or you could upgrade to Sky Q, for which Sky do provide engineer support, or Sky Stream which doesn't require a satellite dish.
