Hi, I have just bought 2 new sealed beam headlight units for my 97 defender,after a rather dirty visit to Devils pit on sunday, they fit just fine except for the large rubber seal on the back that keeps it all water tight, the old unit had a removable bulb and the seal fitted real snug around the back end of it, the new unit doesn't and therefore doesn't hug the back of the unit very well. Do I have the wrong lights or can I buy a suitable new seal from somewhere. Yours hopefully Frogmeister