I am allergic to lanolin too but vaseline is very good. I was told by my podiatrist that before going to bed, to slather on vaseline after drying my washed feet and then to wrap my feet in cling film bfore putting on dry soft socks . Leave it on till morning. It worked much better than just vaseline alone!

I am diabetic too and cracked heels are a definite symptom sad to say. Sometimes the cracking is caused by a fungal infection (NOT athletes foot though) and I have used a cream called tretinoin on my feet which cleared the cracks in days!

Good luck getting rid of them because I know how painful it can be.