There are numerous sea fishing tackle shops across the North West of England and Wales. Most also have a fairly steady supply of fresh and frozen baits. Llyn tackle shops.
Some of these are more geared towards baits and rigs whilst others are like Aladdins cave, literally everything within 4 walls. The interactive map below has info on the location and websites of coastal tackle shops across the Llyn Peninsula. If I have missed you off and you would like adding let me know.