If it is an old climber, then it won't suffer from being "mowed" But it would be a good idea for you to tidy up the ends of the canes if they are shattered. Just prune them off below the jagged tops.

If you leave 5 newer canes and remove the greyish old ones, that will also give the rose new strength. Fish fertilizer is like chicken soup for roses if they have had a shock.

Thank you. I was fretting about it and after I posted I decided to go down and tidy it up just like you are suggesting. Cleared what grass was there away from it, added some new soil around the plant, then mulched. I saw leaf nodes so was careful not to mulch over them. Is it to late to fertilize? should I have done that before I mulched? I can push it aside. I'll check into the fish fert.

This is a good time to fertilize. It will be good for the rose after being hit with a mower.

You might also consider putting up some sort of tripod, post, or obelisk that you can wind the canes around. It will help future mowers to see the rose, and provide the climber with support.