Hi there
Did the very same thing with mine quite a long time ago, the local Land Rover specialist hadn't got the tool to remove the injectors and i needed to replace them as they where faulty so i took it to them to put it on there test book to recode the injectors, as you said remove the rocker cover etc using a towel and a piece of wood over the top to stop it from flying out and causing damage to the bonnet.
They weren't to chuffed because they had told me it couldn't be done with out the special tool!!!!!
Regards
Nick