Nuevo Habitation Battery

Hi Guys, I have had an 08 Nuevo ES since early 2013 and replaced the habitation battery in 2014 with a Numax XCV35MF (120AH), and purchased a CTEK MXS 7.0 smart charger at the same time.  The charger can be left connected to the battery and will charge it as and when needed to prolong battery life.  Over the last 18 months I have only managed about 20 nights away and the rest of the time the battery has been connected to the charger in front of my garage.  The battery voltage was showing low and the charger was much warmer than usual a couple of months ago so I thought it was time to replace the battery (7 years is OK), and I replaced with another XCV35MF.  To my surprise the charger is still hot and on the van control panel the voltage reading isn't as high as I expected.  Habitation battery: 12.1V and Vehicle battery also 12.1V.  I measure the voltage across the battery terminals with and without the fuse connected and both readings were 13.1V.  The control panel is also indicating a slight current drain on the Habitation battery with everything switched off so I removed the battery fuse and measured the current.  This is showing as around 88mA with everything off so that would mean I am using around 2.2A per day.
My question is: can anyone confirm if this is normal or do I need to investigate further?

That's a bit confusing - the control panel shows battery voltage as 12.1V but it's 13.1V when you measure across the terminals? It's not unusual to see slight differences, but typically I would not expect that to exceed 0.1V with modern voltmeters. There will be small voltage drop along the cables, but with only tens of milliamps flowing it couldn't realistically explain a 1V difference.

Current usage will vary depending on a number of factors, such as which make/model power controller you have. Assuming the power control system is turned on, tens of milliamps seems typical for an earlier Sargent system (EC325/328) and possibly even a bit low for one of the later x00 series.