HI Wheaty98,
You can register / replace / remove up to 3 devices per month, and each action counts as 1 change. Personally, I'd suggest replacing one of the duplicate desktop devices (whichever you use the least) with your laptop while you're on holiday.
If you don't use your laptop when you return home you can always change it back again as this will only count as 2 changes (if done within 30 days of the first change)
You can manage your devices in the TV GO app in Settings (cog icon) > device management.
Let us know how you get on,
Zoie