Planting position for Chaenomeles speciosa Nivalisr

Yes they can - you might find they get a bit more sprawly and spread out more, so I'd expect Nivalis, the one you've mentioned, to reach a height of about six feet and a spread of 10 feet.

Thanks Bamboo, having just dug part of my border I am now in the process filling it with a few shrubs, plants and maybe a couple of fruit trees, it looks quite bare at the moment but in time it will fill out when they get established.