I currently have Sky HD+ in the living room and wish to use the two spare outlets on the LNB to feed the Sky+ box (which I used before getting HD+) to have Freesat+ in the kitchen.

How do I obtain a card to achieve this

Peter

If you want to view channels you don't need a card but the new white Sky card would get you about 5 extra channel that you might watch or not.
If you pay Sky £120/year they will let you record on your own box
If you ignore it & pay £250 once only you can get a Freesat Humax HDR & watch 1 while recording 2 channels (usually)
Keep the Sky + box to act as a backup player if you wish to watch something when the Humax HDR is too busy.

David

If you ignore the deliberately misleading information from SWIZZ?, the same £10 per month will get you multiroom (which reqires BOTH boxes permanently connected to the phone) - this gives you all the SD subscription channels you pay for on the second box, plus recording.