my girlfriend and I have just done the same thing, without the dog. We had jobs in Nigeria, so we drove down in our old Range Rover. We spent about a year there.
1. If you're going to be in Lagos, it's an incredibly unhealthy environment and your dog will suffer with the heat and humidity - it's unrelenting - let alone the disease's the other dogs have.
2. Is your Land Rover right hand drive? If so, it's illegal to have it in the country. We thought it was just the police trying to extort money (it normally is) but a solicitor friend found out it's true. It's not too much of a problem, but you will get hassle at the *many* police check points and they'll threaten to impound your car - which can always be settled with 500 or so Naira (two pounds). I've just noticed that it says you're in Italy, so you may have a left hand drive.
Not directly relevant to your question, but it may help.
If you have any questions, then send me an email.
[This message has been edited by BenW (edited 25 August 2005).]