If you look hard enough, you can find allegory of anything in anything, whether or not the allegory is actually there or not. The fact is, only the author can say for sure whether there was any allegory, and as we have several instances in which Tolkien vehemntly states vehemently that there is no allegory in LotR, we just have to take is word for it. When the author says it isn't there, no one can say otherwise. Now, there might be influences from the author's life in the story; that's natural and uncontrollable. However, influences do not mean allegory. Allegory is the conscious decision of an author to have their writings be representative of true events or symbols of deeper meaning, so again, if he says it isn't there, it isn't there.