story identification - A book I read based in England

I read a book or series of books around 1992, and these are the things I can remember

• if it's a single book it is very long, otherwise could be a series;


• I'm pretty sure the protagonist was a young boy;



• the protagonist had to collect a number of objects which were circles with a cross through the middle;


• the objects were all similar in appearance but were made of wood, iron, etc. ;


• one of the objects was somehow related to water and found on a viking ship;


• there was a cyclic event of "dark forces" that the protagonist needed to combat; and


• the year the book began there was a particularly harsh winter and this was associated with the activities of the "dark forces".

Answer

This sounds like The Dark is Rising, the second book in the The Dark is Rising sequence.