I am very new to modding so I went on to youtube and watched a few tutorials and I now have two blocks in my mod one extends Block and the other extends BlockContainer.
The problem is that my regular block has no custom rendering I can however be pushed. as soon as i convert it to a BlockContainer (hence a tile entity the piston can no longer pushed it, now this doesnt seem right as rails and pane glass (blocks I am using as reference) can both be pushed by pistons and both are definitely custom rendered.
As i understand it the blocks can't be moved because of the attached data, so i would be in favour of removing tileentity completetly, however http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/mods-discussion/1410896-question-custom-rendered-block-without-tile suggest that its not possible to have custom rendering without tileentity.