Acer has lost it's vibrant colour

What time of the year did you buy it? It may have been taking on it's Autumn colour early. I don't think there is anything wrong with it.It would not change it's colour other than Autumn or if it was in a pot ,it could be starved etc.

Thanks for replying. Can't remember exactly when we bought it. In autumn it doesn't have this wonderful red colour, it's colour stays the same dull colour until the leaves fall. Why could it be starving? should I be feeding it?

Is it a bit exposed? Acers do prefer to be a bit sheltered. I think that Wyeboy meant that if it had been in a pot for a long time, it would have used up all the nutrients in the compost. Try a general feed, I always prefer blood, fish and bone - sprinkle some round the trunk on the soil. The rain will wash it in.

Thanks Spritzhenry...will try the blood, fish and bone mixture. Should I use this mixture as a general feed for other trees too, such as Eucalyptus, Weeping Birch and Laburnum?

I would say it's a bit late in the year to be feeding anything. If you feed now, you will encourage your plants to make fresh growth that will be hit by frosts in the autumn, weakening it. Better to leave it now until early spring.
Also, for best autumn colour in trees, we need a combination of warm days and cool nights as the days shorter. If we don't get this, autumn colour tends to be disappointing, so keep your fingers crossed we get the right weather this year

In the spring, when you do feed your Acer, then the b, f and b feed will be fine for your other trees. It gives them a real boost.