Any document issued by a government that mentions your name and UK address should suffice.

Have you tried this? As far as pp from Interrail told me, it’s not enough to have that. It needs to be a document issued by UK which specifically says that I am a resident. 

What I have so far is (or what I can get):

Council Tax Bill In my name with my address.

NHIC Issued from UK - Valid only to UK residents

Romanian Passport - Which clearly states that my residence is in UK

National Insurance Number Letter

Settled Status Printed Letter - I can also provide an online share code on the spot to prove I have it

Gas, Utility Bills - In My Name and Address

Rent Contract - WIth the same address and my name

Work Contract - Proving I am employed in UK

Letter from Work confirming I work for them

Any of these are good? Has anyone actually tried on board a train to prove UK residence with any of these?

You are worrying unnecessarily over this, it is hardly unusual for people in Europe to have different nationality and residency.

It is very very rare that anything beyond the passport would be asked for by train staff, even asking for ID/Passport is the exception, even then it is just to match the name or see something that indicates the person is a visitor.

Only in Romania would it make any difference for your travel entitlement having GB instead of Romania as your home country on your Interrail. In every other country it makes no difference which you are from as the pass is equally valid.

Take whichever one of those you prefer, the Health insurance card, as you will want to have that on you anyway is probably the best.

Trust me I know haha. The worry came from the Interrail people who are so useless it’s crazy! They neve can give a good answer and they even said that they have no idea what document to use!! Even though it’s a matter of receiving the profit (by the train companies) from their ticket! So they make up the rules! As long as they agree on a document proving the interrail ticket is valid as a UK resident with settled status using a EU passport is ok, then they receive their share of the ticket and would have no problem but they can’t even do that! 

And I imagined that this issue is quite common as well, but the worry is that I cannot find any info in other forums either. All other country of residence issues I found in other forums (including here) has to do with Citizens of other countries from other continents!

Anyway thanks for the answer. Any comment like yours serves to calm me down a little more. But it would be very helpful to find someone who’s actually tried this and can tell me if someone asked for proof, what they showed (if they did) and how everything went! So keep the answers coming if anyone has them. This thread can also help people in similar situations worrying about this.

I used interrail already dozens of times, and never, ever, ever I was asked proof of my identity. When I was asked for an ID, it was for a border crossing, not to check your tickets (Eurostar, or an  occasional check on the Dano-German border).

It’s mainly weird because the UK doesn’t have an ID-card sytem like other European (EU countries). Most common things used when lacking ID is a passport, driving licence, health insurance card, sometimes even credit cards. One of those will suffice to prove your identity (of which the chance that it gets checked is 0,01% or so).

No need to trot around your tax bills, or contracts during your travels .

It happens mostly in Switzerland.

Yeah they often check whether the names match (maybe birth dates too).

They won't care about the country in any case, that's not their job.