Garmin Edge 800 GPS bicycle satnav (Ivy Farm SK11)

Old (circa 2010-ish) but in working condition (but no manual), complete with UK O/S maps and Garmin European city maps (on 2 separate microSD cards), handlebar mount plate + 2 (perished) 'O' rings included for replacement reference only), a pedal cadence sensor (but both pedal-crank magnet and zip-ties have gone missing / not included) which may or may not be working but certainly needs new CR2032 battery.