I have an apple tree in my garden with no clue as to what species of apple it is. The tree has been in my garden since the house was built in 1938, and probably before that. It is a self pollinator and the fruit ripens quite late, end of September, early October depending on how much sun we have in the summer. Usually the tree crops very well, this year it has been phenomenal. The apples grow very big, much bigger than commercially available apples and have a crisp texture, and sweet flavour. One side of the apple is rosy red, the other green. The most unusual thing about them is that they 'fall' almost like a cooking apple. As we also had a Bramley apple tree in our garden, I wondered if it was some kind of hybrid. No-one seems to be able to help with its identity, perhaps some 'older' gardeners or orchard owners out there may be able to help. Or, is there somewhere I might be able to find out. There isn't any particular reason for knowing, just curiosity.
It may be a lucky planting of a seed - many years ago. If you plant a seed of an apple and it turns into a tree, it will not always produce the same apples as its parent.
But now is the time to take some of your apples to an Apple Fair - see if there is one on near you soon. There are some in Oxfordshire, I know. There will be an expert there who can identify it if it is a regular variety.
Thanks for the responses, I have heard of a Blenheim Orange, although never tasted one I don't think, but not heard of a James Grieve. Will have to see if there are any Apple Fairs, although this is RHS is a good idea, will have to look into that. Whatever they are, they are very nice apples.