Does my X1 Carbon 5th gen battery need replacing?

Hi,
I mostly use my X1C 5th gen via battery power since bought brand new (18 months old) and in the last few days I've noticed that when the battery is down to around 30%, a few mins later it jumps to 6% and then suddenly the battery is dead. I've already done a battery reset/re-calibrate but this has made no difference. However looking under power status settings, it seems the full capacity of the battery is now only 35Wh, down from the factory capacity of 57Wh. Is it normal for the battery to lose capacity from 57Wh to 35Wh after only 223 charging cycles? The laptop is only 18 months or so old. If i really need a new battery, where would be the cheapest place to buy a brand new, genuine Lenovo one? Ebay? I'm located in UK, if it helps.
Many thanks

 

Check via HWInfo64 iirc it also has some information about the battery.

Though if they are pulling from the same sensor then it might be the same info.

 

Thanks, HWInfo54 is reporting the same:



But is it normal to lose ~40% of the battery capacity in only 223 charge cycles in 18 months? Perhaps I've been wearing out the battery quickly by only connecting the charger when the battery drops < 10%? Is it easy to change the battery on the 5th gen X1C?

Cheers