Nearest of the ones I know of would probably be Newton Hall Farm, on the corner of Saughall Massie Rd and China Farm Lane - contact no 0151 625 5990
Also next door is China Plate Farm, think they do hay - 0151 625 8698
I've also used Broster's (Prospect Farm) in Saughall Massie in the past - 0151 677 2720
There are a few others I know of, but probably too far away down the Wirral for you. I've not used the first 2 myself, and it was a few years ago that I used Broster's, but hope that helps.