I am driving my SMB in Germany (7.3 Diesel) and bought it from Arizona
I think all the regulations to get an homoligation here is all the same now in europe (theoretical).
If you are working for the army there are other regulations because than the vehicle has an army registration. Much easier!
I needed to switch lights in rear and front. You will need yellow flashlights here and they are should flash while braking. Also you will need "E" certified headlamps.
You also will need emmision papers for your rig. That should be no problem for your´s.
Off course you have to pass the mechanical check here....
No worry about this all. There are a lot of Econoline here ind Europe! Also to get parts here is no big deal. You can order it at o lot of onlineshops and get it after some days. BUT the price for it is much more than yours! TAX, Custom fee and shipping from US rise it up to the moon!
Think about it twice, if you do not have a very special van it is not worth ti import it to here. Econoline are very cheap here in europe because nobody like the big V8 for dayly use (price for gas and the registration tax is amazing high). So better buy one here. Maybe you can get than an right hand drive what makes sence if you will use it in UK. Or buy an europe van if you just need a van for transport without emotions
Do not forget.
add tax and custom fee (together about 30%) to the worth of your van including shipping costs. That is what they want to get from you before registration.....