I have read all your replies and looked at similar posts as well over the 3 weeks since I joined this community. Many thanks to you all. I feel much less isolated and much more enlightened now.
My husband phoned the Osteoporosis Group nurse for me (I am quite deaf and not good on phone). She related to my situation immediately and and shared her knowledge freely, answering all our questions about time on biophosphonates, alternatives like Strontium Ranelate etc. At the end she encouraged me to consult our GP whom we have now seen.
On GP's advice I am now taking a "Fosamax Holiday". I have been put on the list to have a bone density scan (the last was at least 12 years ago) and have it assessed by a Rheumatologist who will then discuss whether I should ever go back on the medication again or not. In the mean time I will continue taking 'Adcal-D3' (Calcium and Vitamin D supplement) and try to keep up my daily attempts at weight bearing exercises, which include 30 minutes of (not so brisk any more!) walking.
I will update again after the bone scan and consultation.