I think I must have grabbed one of the last sub frame tanks. it has just arrived here in New Zealand. payed the dam customs duty today and should be here on Thursday
Tried filling my original subframe with hot water and it leaked around the inner part of the grab handle. ( is a 2012 fe 570) would have converted it if it was not for the leak. looked long and hard for a suitable epoxy glue but came up with same answer, " it will eventually leak" plastic welding may work.
also built a front tool box that sits in front of the motor. It contains a custom built removable 3litre fuel tin and a few tools. that could be an option for thought.