Try a good fruit nursery like Ken Muir. You should be able to get maiden trees on M27. Have you got other apple trees nearby as it will need to be poliinated? Or you could try a 'family tree'. These have 3 varieties on one trunk. I have one of these and it works quite well, it's also on a dwarf rootstock. Don't ask me where it was from (Woolworth's!!).

I agree mine grow very well and they are on something like M 27 which means that they are easy to reach

We have 6 pear and 6 apples in a 40 by 50 foot garden. They are pyramids and ballerinas on limiting rootstocks. I have grown cordons on limiting rootstocks in a previous garden. As mentioned you need to check if they need a pollinator. They can be temperamental and crop heavily one year and hardly any fruit the next year. The ones we have keep upright and narrow and are about 4 foot apart. They can also be grown in pots too but would need a lot of watering in a hot summer,if we ever have one

To avoid the alternate years of cropping you must thin the fruits just after the June drop. This way the plant won't wear itself out. As for you though....!

You could also just go for a truly self-fertile variety such as Scrumptious. It really does live up to its name with a reddish skin but a flavour more akin to Cox's, heavy cropping in any part of the Uk (great feedback from customers growing it up in Northumberland).