I’m using Natwest just for a savings account so I transfer the money to the current account and it goes to savings via a standing order.
I’m curious how much you have to do to keep a current account from being closed due to inactivity or is that not a thing? Is what I’m doing enough because there is some activity or do I need to leave money in there as well 
I’ve only usually ever had one account that I do everything with so never been an issue for me before.
The usage you describe is pretty common. The standing order adds further legitimacy to the account.
If you feel uneasy (and you shouldn’t) leave £10 floating in the current account.
It’s all good. 
It’s only because I read that if you don’t have a current account with them as well the only way to withdraw from the savings account is via a branch! 
It looks like you are doing more than enough. You have funds coming in and out. What more activity do you need? That’s good enough, relax and enjoy the benefits if any.
I just leave £1 in my dormant current accounts. I’ve seen in T&Cs for some banks that they reserve the right to close your account due to inactivity but it’s usually a couple of years or something like that. It’s never happened to me, though.
I left £10 in my First Direct 1st account for 12 months, during a break from their RS product, and was surprised to see on my credit report that the account had been deemed DORMANT.
That disappeared once I started moving a £1 back and forth every now and then.
Co-op reported my current account dormant to the CRAs after just four months of inactivity, though did have a zero balance during that time. I had only opened it for the CASS bonus tbf.
I now send £1 SO between my two unused accounts, once a week, back and forth, (a) to keep accounts live, and (b) to register activity for the YouGov Finance data bribe 
Yes it seems to be all about “activity”.
So to put it to bed, maybe set up mirrored standing orders between your external account and Nat West as described above. Nice and simple.
Sorry to briefly re-open this but I wouldn’t even worry about doing this @Ryan - I’ve had a dormant NatWest account for years now. And never have they bothered to write to me or note it would be closed or anything.
It was last used in 2020 for a while, I’ve had it for 20+ years.
At NatWest, we class a bank account as dormant if it has not been used for 5 years or more.