Hello,
First thing's first - continental rabbits need BIG enclosures. Most people actually have giants (i.e Conties, Frenches, English Lops etc) inside as it's easier to provide the space and stimulation they need inside the house. If your new measurements are correct, then I make that out to be 34 square feet (5.7ft x 6ft). This is still too small for a contie, unfortunately. Small/medium rabbits need around 44sqft minimum, to put it into perspective. 32sqft is not enough for a contie, unfortunately. What sort of set up do you have at the moment? Is it a hutch and run, or a shed, or an aviary, or what? Photographs would be a great way to help advise you on what to do.
Another thing - rabbits don't need heatlamps. Unless it was freezing (and I mean seriously
freezing, not just 0 degrees - think arctic winter) then they'll be able to grow a coat thick enough to cope over winter. Lots of straw in their hutch/shed/housing is also recommended, just to help them cope a bit better.
Rabbits need company, either in human form or other rabbit form. Guinea pigs are NOT a good idea, especially with a giant rabbit. Not only is there the risk of bordatella being passed between the two, resulting in illness, (more advice here:
http://www.rspca.org.uk/adviceandwelfare/pets/rabbits/company/rabbitsandguineapigs) one kick from a continental could easily kill a piggie. The best sort of friend is another bunny, and it's even better to adopt from a rescue center. That way your new bunny will come spayed/neutered, vaccinated and health checked - saving you £££.
Is your boy neutered?