I feel your pain Dave. I managed to get mine offline just last week.
I had done a backup on the device before I started messing with it, so I wasn't too worried. I figured I could do the reset and restore before I figured out how to use a telnet program. I was wrong. Very, very wrong.
I found that using the erase button also erased my local backups. It seems to be the default setting for these. I have now changed mine. I found one eventually that was quite old, but it needs some tweaking to be sure..
Your only option is to erase and restore your remote backup