Hi Nick, you could try a Jiggle Syphon https://www.amazon.co.uk/Hyfive-Priming-Jiggle-Syphon-Transfer/dp/B00KE0GTPQ/ref=sr_1_4_sspa?crid=2K15TUKB0OSGG&keywords=jiggle+syphon&qid=1642157102&sprefix=jiggle+%2Caps%2C91&sr=8-4-spons&psc=1&smid=A3UZTDMDZ5GUQW&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEySUFKQlVWRk1CT1ZMJmVuY3J5cHRlZElkPUEwMDA0NTg1REVRR1ozS1VESzdVJmVuY3J5cHRlZEFkSWQ9QTAwMTY5ODVaUDJRUU9HMENVN0gmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl
The only thing to consider is having got the fuel out what do you do with it due to all the laws now about safely disposing of hazardous chemicals etc.

If your tank has got space in it then I would suggest that it may be better just to fill it up with Esso or Shell premium fuel with a gerry can so that the old fuel is diluted and mixed with the new fuel and ensure that you then keep topping the car up regularly so that the older fuel is diluted further and further with new quality fuel.

The tanks are foam filled, so sucking out the fuel will be difficult

I'd jump the fuel pump relay, split the fuel line at the connector where it comes up the NS bulkhead, and pump the fuel out using the in tank pump

If you do let the fuel (some/all) go through then try some of the injector cleaner afterwards in case any of it was sticky ?

Once out and running make certain you give it a longer run to get it hot all the way through so it combusts fully and the cats don't suffer. An Italian tune up of sorts.

As for your fuel, the traditional advice for mild steel tanks is to fill with fuel to prevent oxidation occurring but I have never been keen on this because the headspace is not protected and this is where oxidation is likely to occur.

The most important factor is to keep the inside of the tank free from moisture, a flush with nitrogen would be ideal but this is probably not practical. In the winter there is not as much water in the air so it is unlikely to be an issue if the car is kept inside and is a few degrees warmer than the air outside. so my advice is to drain the tank and put some silica-gel in a bag and drop it into the tank on a string to absorb any moisture.

I don't have to tell you that a nearly empty tank is the most dangerous so make sure that there are no static or other ignition sources close by including your clothing.

If you decide to fill with fuel it probably does not matter too much as most fuels contain an antioxidant additive but as I said before this will only protect the wetted part of the tank.

The fuel will need to be changed in the spring to replace the lost light ends and give the old girl a fighting chance of starting.

What sort of 'problems' are we talking about here? I've occasionally left my 4/4 standing for a few months and all I do is start it up, take it for a good thrash to get everything nice and hot, and then fill it up as normal. The only issue I've ever noticed if it can be called that is that it takes a few extra seconds cranking on the starter to get it fired up, which is in my view a good thing as it gets the oil circulating round the engine.