Tri gear bungee tension

[Richard <riddon@btinternet.com>]

Anyone got any good idea's how to re-tension the nose gear bungee on a tri
gear with the engine and firewall in place? 

Mine has been under tension for around 6 weeks and seems to have lost some
of its original tension. It was very tight to start with but the nose gear
pivots off the bump stop now just with the weight of the engine/prop so I
obviously need to re-tension but can't see an easy way to pull, hold and
take up the slack whilst lying on my back underneath the fuse.

Richard Iddon G-RIXS