Found this 12000mah USB power bank on CPC.
Cheaper than I could find elsewhere, even cheaper than int'l Ebay sellers.
CPC say 'unbranded' but its a 'Reviva'. See (my poor quality/dirty) photo (it was as-new when it arrived..)
I was a bit skeptical at the price but quality seems good.
Comes with adaptors for old iphone/ipod, microUSB, miniUSB. Came about 85% charged.
CPC free delivery over £5
Portable, high capacity 12,00mAh powerbank charger. Sleek and compact design with a gloss black finish.
Two full size USB outputs; simultaneously charge 2 devices
2.1A output (Output 2) is ideal for recharging tablets
Multiple charging tips cover most devices
Compatible with all standard USB charging leads
Integrated LED display shows remaining charge
Recharges via USB connection (charging time up to 17 hours)
Dimensions (HxWxD): 22x77x95mm