) gurgled happily, sounding much like they were saying :

I recently moved house but rather than sell the old one I tried to
rent it out. Unfortunately the tenants smuggled a muddy dog in and
the estate agent tells me it stinks of dog and cannot be cleaned out,
so I need new carpets.

raises eyebrows
I'd have thought a bloody good shampooing should sort it, together with a
thorough airing.

The estate agent has recommended "trade carpet". What is that and where
can I find it?

Assuming he doesn't mean a particular local supplier called "trade
carpets" (Yellow pages?), he means "thin cheap ****e carpet".

I suppose I should get a dark colour to hide stains?

Only if you want the place to look small, dark and claustrophobic.

Should I tile or use laminate in some areas as these may be
easier to clean?

Using carpet in kitchens and bathrooms is a revolting idea. Put a door mat
inside the front door. Everywhere else, it's really just a decor thing.

Oh, and choose your tenants better... Make sure the rental agreement covers
the costs of cleaning, and if you don't want animals in the place, make
sure it says that...