Looked around in the UK and the cheapest Line 6 Variax Cabled Power Kit I could find was Â£99.
However Digital Village (DV247.com) do the A/B switch for Â£22.70,
Official Line 6 Power adapter 9v 2000mA on ebay.co.uk around Â£18,
TRS Cable Â£12.00,
XLR Cable Â£14.50.(optional if you want to go acoustic in PA)
Admit you have several packages to wait for but 1/3 off seems good to me.
Hope this helps others wanting to save battery use.