I found my way in. You remove the top, remove the back with 6 securing screws two cross heads at the bottom two 7mm at the top and the two recesed 7mm which you can get out by forcing one leg of long noise pliers in on a flat or simeler and turning. slot these with a hack saw to re-fit. There is also two 7mm inside the top on the bar. Remove the cercip and washer which is behind the plastic cap that retains the drum.
Yours Charlie.