Product thumbnails not inline with left margin

Hi there, my site is suffering from poor alignment of the product gallery thumbnails and the main product featured image. I’ve had a massive look a the support forum, and am beginning to think it’s time to get my fingers dirty with a bit of custom css. Being a bit of a css virgin, I find this a bit of a concern..
Here’s a link to my site https://buywoodengifts.co.uk and the problem is on every individual product page for example on this page https://buywoodengifts.co.uk/product/personalised-carving-board/ you will see that the first image in the product thumnails is well to the left of the visible edge of the main carving board image.
I just would like to tidy up the alignment so that when/if I add a sidebar to the product details pages, the thumbnail images don’t overlap something.
As I hinted…I’m a bit of a newbie (I’m quite good at fashioning Oak, not code!) but if it’s a bit of custom css that someone could kindly post for me, I’ll research further to make sure I can insert it properly, and in the right place.
Many thanks (many!) for any help