H1 won’t align with the top of an image

When I insert a two-column row and put paragraph text in one column and an image in the other, the top of the text lines up perfectly with the top of the picture. But, if I make the first line of text H1, then the top of that text displays below the top of the image. It looks as though I hit Enter accidentally. Of course, I did no such thing, but I can’t seem to do anything to change the way it looks.

Here’s the link: http://www.gvzglasshouses.co.uk/greenhouse-heating-winter/#more-16128

No CSS please. I’ve been warned by the webmaster not to meddle with the theme.

In any case, the text and images should function as I have described without the need for any coding.