My calming space invaded

I'm already high anxiety after a hectic weekend and also embarrassed myself. Thought I'd do a few hours at the allotment today as it's my calming place.

A bit of background...when I started there, an elderly chap was struggling to tend his plot so I thought I'd help him. He took my kindness the wrong way so I had an 80 something year old say i had a nice bum? do i want a massage etc. Get in my space etc so I avoided him as much as i could.didnt talk to him. Hes still trying after months of avoidance.

I put a mesh fence around my plot to keep him out and my son and i and our dog were having a nice time quietly and our dog behaved. The old guy in question starts calling my dog, my dog runs across another persons plot! I grab him and ask the guy to please go away as my dog now wont settle. 

He comes back same again, then asks do I want a cucumber. Then again do I want runner beans, flowers, potatoes, something I couldnt understand. Each time I say no please go away.

He then tells my son off for not helping me! I say hes now having to hold the dog on a short lead as you keep calling him please go away. Then hes back again do I want a I'm using a mallet to put fence posts in....but he brings me a hammer anxiety is reaching melting point. Please go away I'm not getting anything done....hes back, do I want my strimmer taken apart!! Then picks it up! I snatch it away saying please just leave me alone! I cant be clearer. I'm almost at meltdown....I have to pack up tools etc before I leave though. So this time we sit behind tall sunflowers as we see him approaching. Hes yelling my name, I'm trying hard not to cry. Hes there for 5 minutes then goes to his car. My son says hes looking st us from his car window. I look hes sat there with what may be binoculars. 10 mins later he leaves

I'm now more stressed than ever. I got to my room and cried, even my wedding bands now annoying me, I cant talk, when I talk to my son the wrong words come out.

I dont know what to do. He has a wife and family at home so hes not lonely. another plot holder turned up bit later but he bugs me. 

I'm now so tired. I started getting anxious about it all over agagain.

He may be senile but hes causing me to get overwhelmed. I'm trying so hard to not meltdown. His wife wont listen she makes excuses for him. I dont know what I can do