The official way to tax your car is
First of all you must go to the income tax office and pay D100 to pay for the MOT you then take this receipt to a Police Station which does Mot's they 'should' check the vehicle and then give you another receipt and a cardboard disc, you then take these documents back to the tax office pay the Income Tax get another receipt and get your second disc. At all times at the Tax Office you must have a TIN Number. depending on when you go for this can take minutes or days, this year took us 10mins for the MOT and 15 mins for the TAX. If you are based in Bijilo then you should be able to use the Tax Office at Brushubi. This year we had to replace our TIN number and it was applied for and printed off immediately, however because of our location we can use either Brikama or Brushubi Tax Office as it depends where you live to which Tax Office you can apply. The year before last you were supposed to get interviewed by the Tax Office, which was a bit if a pain, but not to traumatic. The cost of Tax for a normal or tourist (not tourist vehicle) is dependant on the weight of your vehicle they reduced it to 2.4t, basically if you have a 4x4 then the cost this year was D3000, also this year you had to produce and leave with them a copy if your insurance. There are different ways to do this process, some insurance companies will now do this whole process for you at a fixed fee. However we have always decided to do this for ourselves as this way you will always know the correct procedure and if it takes a few days - well what else have you have to do.
If you are based in Bijilo then you can use Brusubi Police for your MOT.
My understanding on Driving Licence is that you can drive on a UK Licence for 3 months, then you must have a Gambian one, which officially you cannot obtain without getting your residence permit first. To apply for your first one all you need is a copy of your UK Licence and the fee. The following year it does get easier as all you need is a copy of last years licence and again your fee, however again it depends which official you get when applying for your Licence as to whether you need to produce your residence permit. Think the fee for this is still D500
To legally drive you need 2 triangles a jack and fire extinguisher, make sure you get one without an expiry date on it.
As previously said the info for commercial vehicles etc. This whole process sound bad, but really it's 100% better than it used to be also think about when you want to tax it again as previously said and only factory fitted tinted glass is allowed and must get a permit from the Police Station
Hope this is as clear mud because reading it back it seems to me.