My $0.02. Hold onto the bike only if you can get it to be comfortable, safe and enjoyable. From your description, it sounds like there will be some work/money to get your Holdsworth and your body to be comfortable. About 4 years ago, I decided to fix up my 30 year old bike rather than buy new. My riding sounds different than yours so keeping, upgrading and refitting my sentimental bike made more sense to me than a new bike. The biggest lesson I've learned is fit matters as much as the amount of time I need to dedicate to stretching and strengthening. The 30+ year old bike is fine but my 54 year old body needs some work.