As far as MOTs for cars are concerned,if you buy a car in the Isle of Man it does not need a test.If you bring one in from the UK or wherever then after 6 months it must be tested if it’s over three years old or as soon as it’s three years old,and it must be re-registered with IOM plates.There is one testing station here,at Tromode,Douglas and it has a reputation of being very strict.There are more roadside checks here than in the UK,but you are given a chance to put any minor defects right i.e. bulbs,wiper blades,empty washer bottles etc…Defects more serious are not tolerated and you will pay a hefty and I mean a hefty fine if caught.All HGVs with three axles or more were subject to an annual check - not MOT - but since the fatility when the wheel came off a DAF tipper it looks like a UK style annual test is coming,including 3.5 tonners.
I was told that IOM drivers used a worksheet on the Island but were subject to tacho regs as soon as they got into the UK.As mentioned,most freight is unaccompanied but removal companies are regulars to and from the UK and even further - mostly for people coming in,not going away from here 
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I packed in driving/shunting in 2005 and have been living here since 2006,so as far as driving regs over here are concerned it’s mostly secondhand what I know.After all I came to retire here,not to listen to some chuff shouting “don’t drop that there” or “can you just nip” 
We are a Crown Colony and have a figure-head style UK Governor here full time.The UK is responsible for defence and customs and we share a VAT agreement with them,although the UK has rescinded that,as well as the reciprocated health agreement.If you have paid more than 10 years into the UK NI then all treatment in the UK is free.If you have paid less than 10 years then A and E is free in the UK but not if you are an inpatient.My wife and myself are lucky as we paid substantial years into UK NI and pay into the Manx NHS now so we are not affected.
Travel Insurance brokers are doing a bomb over here