how about one of them low growing spruces that look like velvet ?

Some of the trailing cotoneasters, maybe?

Presumably sunny situation, as you had a Yucca there - how high and wide do you want it grow?

about 4ft high and the same width

Cistus 'Peggy Sammons', Hebe 'Autumn Glory' or H. 'Midsummer Beauty' , though the last one is only moderately hardy, but does survive most years.

thanks, i did suggest a hebe to the customer and a rhodendrum or a ceonothus but still no joy, cannot think of anything else though