this may be a dumb questions but I will ask anyway, after looking at the "LOTUS ESPRIT GT1 number2 from THAILAND and How to install" thread, it made me think, could the fuel tanks be removed by cutting out a piece of the inner rear fender?
To someone with fiberglass experience it would seem easier to cut a hole replace the tanks and patch it back up..
The passenger tank has the sump, so don't think it would fit going that way.
It might be possible with the drivers side tank, but you will need quite the hole, and likely would have to cut off the transfer elbow.
The passenger tank will come out with removing the intake plenum, the drivers side requires lowering the engine or raising the body for clearance. So it is not necessary to pull the engine to remove the tanks, it is just a lot easier with the engine out.
So compared to pulling the tanks with the engine in and pulling them by cutting a hole, I don't see any time/labor advantage to the cutting glass route. And, you end up with cut and patched wheel wells.
Our advice is to try and do a tank replacement and engine C service and clutch at the same time, thus making it worthwhile to pull the motor. Obviously a total engine overhaul should always include a tank refurbishment if not done.