Help with UCAS after a gap year?

I've recently finished sixth form and have gotten my A level results. I applied for universities last year through UCAS in year 13 which was to study business management and i got a conditional offer to all 5 of my choices. At the time I thought that is what I wanted to do but i changed my mind and decided not to go to university this year and instead to take a gap year to save some money and travel. Another factor was that I wanted to change the subject to criminology as i realised I had no real interest in continuing business.

So I was just wondering how I would go about reapplying in terms of references etc. As my sister currently goes to the sixth form I attended so i'd hope it wouldn't be an issue in asking for any help or references of them. So would i have to create a new UCAS form entirely? Also would it be looked down upon by universities that I have taken a gap year and not finished my previous UCAS application as I didn't want to defer the offers in that subject?

Any help or advice would be appreciated