Many homoeopaths who make their own remedies will make you up tablets suitable for vegans on request.
If you want to buy without referring to a homoeopath, I have used a company in Glasgow which provide excellent service:
who can provide remedies in many forms and will be happy to advise you on vegan options or those who are lactose intolerant.
Weleda, who make homoeopathic remedies, make the following statement:
In typical Weleda spirit, tailor-made medicines and special requirements are available to cater for individual needs, for example vegans who may wish to avoid lactose-sucrose base tablets, or those who may have specific allergies. If you cannot see the medicine you need, please ask your local pharmacy or call the Weleda Pharmacy on 0115 944 8200 for further advice. (www.weleda.co.uk/vegans)