Need to improve credit score, should I close capital one account with low credit limit ?

Purple666

For the last 2 years I’ve been trying to increase my credit rating. Where’s as It’s increased by a fair amount I’m still in the red and i seem to be stuck in the same score for a while.  

The credit accounts I have are - Loan with bank, 2.3k left, never missed a payment.
Retail store account, Credit limit £4000, used £500, never been higher and I've never missed a payment. 
Mobile phone contract, never missed a payment. 
The issue I believe lies with my capital one credit card. 
I have had the account for years and but in the past been over nun limit, missed payments etc.  But I have kept it clean for 2 years now, and I keep the utilisation below 25%. 
Credit limit £1800.

I went on Noddle/Credit Karma to see what was holding my score down. It says my low credit limit is a high risk factor. 
Im very keen to improve my rating as I would like buy a house within the next couple of years. What are people’s thought on how to do so, and would paying off and closing the capital one account help.

Willing2Learn

Hi,
Your poor Cap1 account conduct will have a negative impact for six years, gradually reducing over time.  It has nothing to do with your 'score.'

A mortgage lender scores you against their criteria and policies using the data held in your credit files, added to the data you submit in your application, added to any data they may already hold on you as an existing or returning customer.

[Deleted User]

You don't need to change anything if you're managing your accounts responsibly now.  CreditKarma's opinion on your limit can be ignored.

Pay off your loan and get another card or two to show that other lenders trust you.

DCFC79

Why not ditch the retail account and get a second credit card, 1 with some benefits maybe.