Credit Cards To Improve Rating

Good morning,

I’m just looking for some reassurance I’m doing the right thing.

I currently have an improving credit rating (I’m aware the score and rating mean nothing) My Score is poor due to over borrowing a few years ago and having a satisfied ccj on my file. My ccj is due off my record in 2020.

I currently have a Marbles credit card (£300) I have last week got 2 further credit cards, Barclaycard (£800) and Aqua (£500). I got these as I was advised to.

My plan is to use a cards for petrol, I plan to put £25 in my car on say my Aqua card and then when it needs petrol again use my Barclaycard for £25. Then come the end of the month pay them off in full.

I just want to check that a limit of £800 and only spending £25/£50 on it a month would that be seen as a bad thing?

Thanks