How thorough is the customs search (I head they don't like medical drugs, hypodermics etc)?
I doubt it will be that thorough. Stay relaxed and smiling and you probably won't be searched at all; especially since you're arriving from Iran.
I innocently used to bring a certain medicine into the country for a friend for years before I discovered it contained codeine. Avoid that and you should be fine.
I have bought hypodermic syringes in a pharmacy here so they are certainly not banned. The pharmacists ask why you need them and if you come up with a valid reason you can buy them. I would imagine that traveling around the world with some in a first aid kit would not be an issue.
My reason was to replace the oil in my steering damper and that was OK too.
Do I need to buy car insurance?
No one I know who has visited with a vehicle has ever been asked for it. Moreover, there are no companies issuing it for overseas vehicles (unlike Oman).
What are the port taxes?
Sorry, don't know.
Can I drive with my UK licence, or do I need an IDP?
It's very unlikely you will be asked for your licence unless you have an accident and even then I think a policeman would accept the UK licence. I would say that, like everywhere else in the region, officially you need an IDP, but in practice they are a waste of money.
In my experience, the vehicle documents are always the important ones crossing borders in this region. Less importance is placed on the licence because they assume if you've got this far then you must have one!
How much is diesel?
Don't know, but someone else will.
Any ideas on how to save on the $780 for the ferry????!!!
No, sorry. (But have you tried negotiating and asking for a discount? You might be surprised.)