maybe you could use something like this to change the angle of the drive and then use a drill unit to run it

http://www.ebay.co.uk/itm/Toolzone-Prof ... 20c79e55ed

http://www.ebay.co.uk/itm/OFFSET-SCREWD ... 3f1de50837

or you could use an angle drill unit like this

http://www.kingtools.co.uk/product.php/ ... //sn/49397

that's if there's enough space