Hello,
I need some help with my tortoise.

He is I'm estimating15-20 years old (not sure as previous owners didnt know age), Russian/horsefield tortoise. I live in England, so its not what you call "hot" in this country, and we have an energy cost crisis, where this year im having to cut down on all his heat lamp use, meaning he can not use it this year. Its around 14 degrees i think in the room where he is staying, and can reach 18 degrees. He BARELY eats his food, or drinks his water. When we goes out in the 19 degrees sun in the garden, he doesnt eat weeds, and he used to SO much every other summer. I dont catch him drinking water, and he won't eat his food pellets. He will only eat lettuce sometimes, which i give to him for hydration. He seems regularly active. Not running around everywhere, but he sometimes likes to walk a bit. He isn't really sleepy, in fact more awake this year than previous years when he has had a heat lamp and eaten more frequently. He also seems very happy. Basically he's still fully functional and there is nothing visibly wrong with him. He looks perfectly fine...HE JUST DOESNT EAT OR DRINK. im talking once a week. he is around 7 inches long. Can anyone suggest anything to me to help him or advice or knowledge to keep me at rest? He is also a VERY fussy eater, so i cant just give him any old food to eat.

Thanks in advance