Well I certainly lack the skill to make a reliable identification based on the photograph.
But on any given rootstock a Bramley will usually produce a very much more vigorous tree than other varieties, and, of course, a Bramley is both a triploid and also a partial tip bearer, and as a result of these three properties I thought it was rare to find them trained as an espalier.
For these reasons only I'd suggest probably not a Bramley.
Anyway, it looks like at least a three year old tree. With luck a little blossom in spring and maybe just let one or two apples grow to maturity and all will be revealed. I think that's something really nice to look forward to.