That is true, and I didn't list them as the first two items make the others a mot point, but let's look at them for a second, and do a little elaboration.
1) Captains are hard to come by, and so would be navigational maps that have any form of accurate information on Tides, Navigable channels out of the ships home port, and if you really want to get technical displacement of the ship at it's current laden weight.
2) Fuel, in FO2 you have to get some from the Shi who where making a synthetic fuel. But let's say that in England there is no large group producing it what other options are there? Well in the Fallout universe they have Fission power and that could work for a ship but as you covered before where would you get a captain or crew that would have the knowledge to support such a system even if it was found in perfect working order let alone one that has been standing still for so long all mechanical devices need to be used periodically to prevent them from ceasing up.
OK how about a technology that was invented in England then, Steam powered ships. Well for one while you might find some one able to build or rebuild a small boiler the kind you see at model engineering clubs powering trains, traction engines etc it's doubtful you would find some one capable of finding some one with the skill's, or equipment capable of rebuilding a boiler the size of one in a ocean going vessel but ok let's assume they have one that's working. How are they going to power it? I very much doubt coal is being mined in any quantity and as you rightly say the resource war's would have for the most part bled any resources dry, wood while it is a option the tonnage of good quality seasoned wood you would need would not be readily available, so how about unseasoned wood? Well for one we don't use much wooden framed construction in the UK our houses are only partly timber so we have a source of wood sounds great? Not so, that wood would have been exposed to the elements for nearly 200 years and would be rotted, and rotten wood even when dried out makes awful firewood and to get the same amount of energy you have to burn much much more.
OK so that's wood out of the way, coal out of the way what's next? How about alcohol, people have been making that for a long time and it burns let's explore that. Well yes this one is plausible you can fuel a engine off alcohol but the shear amount you would need makes it unlikely to happen all in one go, but over time it could happen. Even if they made a couple of still's and made as much as they can it could happen without outside help, and they could even take them with them to make fuel for the return voyage, and use the same still's to desalinize water during the voyage.
But with all the fuels I have listed so far there is a problem, that relates to point 1, Skilled crew even today a ships crew have to be aware of how much fuel is used and how that would effect the ship and keep records of it. Let's say he has a 100 ton ship (this is just a mental exercise not accurate) capable of carrying crew, 50 tons of fuel, and say an equal amount of cargo. And when fully unloaded at the draft line it sits at 10ft draft so ten foot from water line to the bottom of the Keel, so the crew load the ship correctly and all the extra weight makes it sit at 17ft draft but was it loaded correctly? or have they loaded all the heavy stuff towards the rear of the ship, so it's not sitting at a angle and the stern is sitting 3ft lower in the water? This would cause problems with propulsion, and how the ship handles at sea. OK so they have loaded it correctly and they are now at sea about half way through the journey and have used 23 ton's of fuel? Have they offset that weight in the ballast tanks? Or if they are using barrels of Alcohol have they refilled the barrels with sea water? because that will effect how the ship handles and so far it's been a relatively calm sea and then a mild storm blows up and it turns out they haven't been offsetting the weight and the ship is riding heaver in the bow (front) and they are taking water on each and every time they have a wave crash over the bow, are they aware of the situation? Are they trying to just pump water? or pump water and offset the way the ship is riding in the water?
OK so they have now ridden out the storm, and the ship made it through OK and they sight land! Great so now they are aware they are close to land, how about where? how far are they from a port that is still useable because a big boat can't just beach it's self gently it's a dangerous task, and as they get close to land they run the risk of running into a sand bar that hasn't been dredged in 200 years and they will have shifted position some what since then. So any remaining marker boys are useless how do they go ashore? Do they have some form of launch they can use? or are they just going to swim for it?
So given all that I strongly doubt he is really English, as just to many things have to come off just right for them to be able to do it, if we where talking England to Europe I would say it's possible as it has been done with far less technology for thousands and thousands of years, but we are talking about a voyage that is thousands of miles in a either vintage or cobbled together ship with a crew that is untrained and inexperienced, and before any one points out the PMV Valdez in Fallout 2 I also happen to think that was a stupid idea by the developers.
Sorry for going on but I found that a fun little mental exercise.