So,
Having worked out I have BAS - what to do with the Basses that I am now collecting.... - I know, I'll make me an A/B box and then I can bring 2 basses with me to a gig and look like a guitarist!
So....
Google, google, google... decided to go with this plan... https://www.generalguitargadgets.com...-ab-switch-box
A couple of trips to Altronics later...
Ingredients list from left to right, top to bottom(where I can remember the price I've shown it):
1 x enclosure - go big(ish) - there's not too much to go in, but it's all in everything else's way - ~ $12
1 x 9v battery enclosure - eBay and ~ $1 not sure it'll be used - it's a big sucker...
1 x 9V battery - from a drawer couple of bucks...
1 x 9V DC insulated jack ~ .85 make sure it's insulated as I have some chrome ones that apparently will cause everything to short...
1 x 9V DC Battery snap - $0.30 (one of the reason for a couple of trips - kept forgetting them)
2 x LED in bezel - went for 3mm red and green ~ $1.85 @
1 x 3PDT heavy duty foot switch - eBayed it ~ say $2
1 x 390 ohm resistor (will be shared between the 2 LED's) ~ couple of cents
2 x mono jacks
1 x stereo jack
1 x instructions
Assorted wire and heatshrink
Total ~$20-$25. Could have got some stuff cheaper through eBay, but couldn't be bothered waiting.