I graduated with a 2:2 in a Bachelor of Technology in Agriculture last year. I have had four years (on and off) experience within research. I wasn't planning on doing a Ph.D at the moment, if anything I was going to wait. However I have found a Ph.D. which I would love as its in an area of great interest to me. I have applied for it. Have I done the right thing here? If not, any advice? Many thanks.

definitely think you have done the right thing; there's no harm in applying. you sound like you have more experience than your usual undergrad.
sounds like you found your niche!

good luck with he applications! i hope you get in! (if you aren't successful, do a masters then re-apply for the following year)