Sounds like they are doing well. Bee orchids have a symbiotic relationship with a fungus, so if you have one doing well, you know the fungus is present and more will likely follow. While light might be a factor, they tend to prefer open grasslands, so I suspect the difference might be in the fungus. If you were feeling bold, you could try transplanting a clump to the back garden in the hope that the fungus would take hold and spread.
Sounds like they are doing well. Bee orchids have a symbiotic relationship with a fungus, so if you have one doing well, you know the fungus is present and more will likely follow. While light might be a factor, they tend to prefer open grasslands, so I suspect the difference might be in the fungus. If you were feeling bold, you could try transplanting a clump to the back garden in the hope that the fungus would take hold and spread.