advice please for climbing rose care

Hi, this is my very first post on gardeners world, apologies if I have posted in the wrong section! I am a super enthusiastic yet totally unqualified gardener! For the last 4 years I have had a love hate relationship with my climbing rose. I have lightly pruned the flowering branches and branches that cross over and tried to continue its growth training by securing and tying in New growth. I have battled greenfly and black spot over the last 4 years to no avail! Last night the storms really gave my climber a right good trashing, breaking branches all over the place! My instinct tells me this combined with my pest problem, cutting the rose right back to the base would be a good idea, however I do also fear this drastic move could kill the plant. I gratefully await any direction you can give me which will help this wee rose.