See Standard Doc 7(H).
An ADF can be used instead of a VOR.
You are required to demonstrate you can tune in, identify (using your extensive knowledge of Morse!), and track a VOR/NDB.
An audio feed from your handheld to one of the rear sockets would probably suffice. Speak to Fred Cross to clarify.
The VOR is on the NAV section so I'm pretty you can't simply jump into a different machine for the VOR part.
Most Jetrangers have an ADF or VOR so swapping hours on machines or hiring a different one is looking the best bet! You can use one machine for the NAV section, take a break and then jump in yours for the rest (if people are reluctant to lend you a machine for the SEOLs).
You might also find the following helpful (if your haven't already read it);
http://www.caa.co.uk/docs/33/SRG_FCL_03_H.PDF