"The Isle of Man has traditionally been viewed as isolated, especially from Britain, during the Later Mesolithic (e.g. Woodman 1978). One reason is that, like Ireland, the Isle of Man witnessed a different trajectory of stone-working techniques to those seen in Britain (Woodman 2004; McCartan 2004), and in comparison to the Neolithic, there was only
limited movement of raw materials between Ireland/the Isle of Man and Britain at this time (cf. Cobb 2007). This has been seen as evidence for social insularity, an interpretation which itself has been drawn upon by some to support an absence of maritime connectivity prior to the Neolithic (Sheridan 2007: 466). "
Garrow, D.I & Sturt, F. (2011) Grey waters bright with Neolithic argonauts? Maritime connections and the Mesolithic–Neolithic transition within the ‘western seaways’ of Britain, c. 5000–3500 BC, ANTIQUITY 85: 59–72
Been like that for a while then....