How can a Muslim build credit score, if credit cards are haram?

I literately have not expenditure - no bills etc. I hardly spend say £1 a month on average. I would like to get a Islamic mortgage in about 2 years but I assume they do credit checks and all.

I have been told I can get a credit card to build my credit score. What I was planning to do is get the card spend like £1 or something a month and set it DD to pay it back or clear it myself ASAP, or set up a DD from credit card to my saving account say on the 12th of each month and then do a standing order back.

I have sufficient funds and I don't really need a credit card, all I need it is to build my credit score.

but the fact I'll be signing the contract saying i'll be paying interest if I don't pay back on time is haram as well (not that I will delay the payment in anyway).

Is there alternative to increase credit score without credit card and not paying bills etc. As I've no need.

Thanks.

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