I’ve covered myself and ordered a 2A and 10A coming tomorrow from Amazon
Versatile 6V/12V charger with automatic temperature compensation protects against overcharging to keep lead-acid and lithium batteries performing at their best.
www.amazon.co.uk
The battery is a Banner Energy Bull Leisure Battery 12V 100/110AH
95751 Banner Energy Bull Leisure Battery Banner, <i>The Power Company</i> have been producing top quality since 1937. Coming out of Austria and distributing predominantly across Europe and Asia. But like all the big battery companies they ship to worldwide distributors. Banner Batteries...
www.tayna.co.uk
Two points jump out at needing cautionary mentions;
1) Charger
The linked smart charger is a 6 and 12 volt charger, it therefore if trying to recharge a discharged battery that is standing below about 6.7 volts will not automatically know if it is tasked with charging a 6 or 12 Volt battery. You will have check its status indicators, and or provoke it to "see" its task is charging a 12 volt battery. If you find you end up stuck locked to it seeing only a 6 volt battery, then come back and enquire how "we" can get over that.
That said, with a 12 volt battery depleted to below 6.7 volts for the duration indicative in this post, its highly likely it beyond practical recovery; LA batteries are very damaged in their purpose in life, storing energy, with long durations highly depleted. Getting one back to stand at 12.7 odd volts is not in itself recovered, it the energy it is capable of storing that determines usefulness other than as a doorstop.
2) Battery
The Banner Energy Bull I found to be a good leisure battery, and has been in earlier times a firm favourite, though there is a significant "but".
That "but" is it is far from a maintenance free battery, in that it in use, it "uses" water, so periodically it needs topping up with deionised water.
The amount, so frequency reflects how much pushing out and taking in energy, along with ambient temperature its been subjected to.
I have known of owners not realising this and readily jumping to denigrate it simply because they had abused it, albeit through genuine ignorance of what type of battery it was.