Pool Light Replacement

Hello

I have just purchased a house with a pool and the pool light is not working. After removing the lamp housing, I found that the lamp was missing, the housing was partially filled with water and the lamp holder was missing . It seems the previous owner did not want the expense of replacing the complete housing, lamp and cable.

The current unit is a Hayward SP0583L . If I am going to replace this I would prefer to have a 12v lamp instead. I have purchased a 100w 120/12 volt transformer and would like to know what replacement housing I should Order

Rgds Richard