I'm sure that by now you might have settled on a pair of speakers for your Arcam amp.
But, if you haven't and for other interested readers, audition the A38 with a pair of B&W 805s. Or better still, if you can get them, a pair of B&W 705s. I have auditioned an Arcam A18/P38 combination with both the 805s and 705s and was impressed. I liked the sound of the 705s better, but that's probably because I have those and am used to the sound they produce.
But, if you haven't and for other interested readers, audition the A38 with a pair of B&W 805s. Or better still, if you can get them, a pair of B&W 705s. I have auditioned an Arcam A18/P38 combination with both the 805s and 705s and was impressed. I liked the sound of the 705s better, but that's probably because I have those and am used to the sound they produce.