You mostly need to have 20-25 kg of fleece for it to be processed to yarn by the big companies. Do a search for small processors who might do such a small amount. The weight requirement is because the machinery has to be cleaned after each batch.
With just 3 small sheep, learning to shear and spin yourself is the best way to go
. Handspinning retains the character of the fleece and it remains something special. You could save up your fleeces for years to get the required amount for mill processing, but it would be a long time before you had enough, and it would need to be stored carefully.
It's vaguely possible that someone, for example on Ravelry (which is a huge international knitting, spinning and weaving forum, which has many British groups) would spin it for you, for a fee. It's worth trying there.
Oh yes, it is 'shorn'