It works out to be great value if you buy it by the litre...

(even if I'll never use it all in 4+ life times )

 You should get some 100ml bottles them sell it for £5 a bottle.
Sell half the bottle and you'll be quids in, plus have loads spare still.

 Yeah someone needs to sell smaller bottles of this stuff for a reasonable price...I reckon I could get the Motul branded stuff(which is apparently the exact same oil) in an even bigger size so it would cost even less to bulk buy...

 Do it, you know it makes sense. You could brand it as 'AgFish Oil'