I did it myself and the tank cost £80, the job took 15 minutes flat and was easy peazy! £70 saved. I'm going to teach myself how to service the outboard and change the oil as well.
For this I need to build a stand.
As I grow older, I'm conscious that carrying the outboard down the steep drive or carrying it up the steps to the back garden area where there is a large dustbin full of water, becomes slightly harder. So maybe it is time for a stand on wheels that can also have a smaller bucket of water and a hose pipe supply for when I want to test or flush the engine through.
So far, a quick internet search shows that these seem to be the popular DIY stands. I have plenty of 10cm x 4cm lumber and some 20cm x 45cm as well. So I guess I can make something. Some scrap 9mm ply could make corner/leg braces as well.
I just have to decide what design to go with now.............................. comments, observations and suggestions welcomed as always