60s print; 4 horses, orange man, poplar trees green/orange/white

I have this wonderful late 60s print on my wall, it was in my parents lounge when I was baby. It's a little faded as it's very old. I absolutely love it and would be interested to know who painted it. I've spent many an hour trying to find it online and trying to interpret the name, but I've had no luck at all I hope you can help me . Any information appreciated greatly, thank you.

I was assuming I would be able to add a photo but perhaps not. In which case the background is a mix of teal, green, I would describe it as somewhat brutalist in style, the outlines are roughly sketched in black, the man, on the left, in profile, hands reaching to the four horses (also in profile) is orange the first horse is an aqua colour the second horse is white the third horse is a slightly greener aqua the fourth horse orange, there are two green popular trees to the right. The top right contains a signature potentially the letters HWEYER Difficult to say, may be another letter between HW and the E. Lettering is narrow with long ascenders and descenders. A comma-like full stop.