Do dogs suffer hayfever,, quite a few times, especiallly when we're in the fields she will start sneezing for a few seconds, stop and maybe not sneeze again that day, this has only started recently (no reason why) could it be the warm weather, pollen or allergy?

Yes, I've had a dog with hayfever.  At least it started with hayfever, then it became full blown allergies :(

My old GSD used to suffer from what we loosely termed "hayfever". He too started sneezing when in grass but it turned into a full blown allergy to anything external and green :(

He had a very nasty rash on his underside, his coat blew to nothing and he basically aged overnight.

Very hard, we tried many things, conventional and alternative medication but to cut a long sorry story short, local honey did help some of his ailments.

On a brighter note, my current bitch sneezes when we're in some fields, she snuffles around so much I'm really not surprised but when we come home again she's back to normal :)

Yip they can just like us :-)  ( she says sniffling  :-D  )