Having just passed the sva light test (hand brake the only failing point to sort this week ) by using the old style 410 bulbs I now need to up grade to a decent brightness.The industry implies that the H4 size bulb is a direct replacement to the 410 but having just attempted it there is a difference in diameter leaving a very loose fitting bulb .Is there an adapter ring to fulfil this task or are the two not compatible? How has anyone else sorted the conversion as Im sure you all have done with viva hc lights ?