The wife suffers badly with hayfever, never had it myself.
She usually takes Telfast, but lately they haven't been working so well. I suggested she try something different, so she went the Beconase nasal spray. This seems to work a treat. I think the body can build up an immunity to the effect medications can have if used too often or for too long, so changing meds is a good tip.
She still uses the Telfast as she has an unknown allergy to something. Has been tested dozens of times for all sorts of things, but they still cant work out what it is. Her reaction is really bad hives, only a jab with the epi-pen works then. So for allergies, the Telfast seems to work well.
Good luck with it, all you hayfever sufferers. It does seem to be a bad season for it.