Got a bit more done last weekend.
Managed to drop the fuel tank to fit my uprated Deatsch pump and have a good look at the bodywork above it.
Minging standard tank, half full of 7 year old fuel!
If you thought there was some sort of fancy electrical arrangement for the fuel level, wrong, it's a float on a resistive arm

Standard pump and filter removed. All in reasonably good condition for 103k miles. Note the plastic pot it all lives in acts like a swirl pot to prevent fuel starvation during cornering.
As the Deatsch pump is a universal pump it wasn't a 100% straight swap. I had to trim the rubber seal that fits the pump into the 'swirl pot' and had to slightly elongate the holes for the outlet/return cap that fits onto the pump. Other than that, all straightforward.
And the floorpan above the tank is pretty good too which is encouraging, despite not having much corrosion protection.
This is the only bit i spotted but it's just a touch of surface rust where it has been rubbing on the fuel tank, so easily treatable.