DesRamsay

I agree and so does my installer - he will install this for me asap.  Many thanks again. 

I don't know if that is 15S or 16S LFP, or some other chemistry. I'll just assume that your float and bulk/CV settings are as per the manufacturer's suggestions.
02 and 11 (maximum charge current) seem a bit low for a 3.7 kWh battery. I'd be tempted to increase these to 30 A (so 60 A when the second battery arrives, maybe cut it back to 50 A).
 
Setting 12, and possibly 13. You are very limited with the voltages there, they are in whole volts. So try setting 2 at 52 V.
Yes, voltage based switching is bad, but it's built-in and convenient. ICC can switch PylonTechs at a specific real SOC, but I doubt that they support your Solar MD. You could roll your own, if you're that way inclined, but it's a fair bit of work.
You mentioned figures like 20% SOC and 35-40% SOC; are these from the battery itself or from the inverter? If you have an accurate SOC reading from the battery, then you won't benefit much from another BMS; the battery is presumably already protecting itself.

I have an Axpert inverter with a single Solar MD Li-Ion 3.7 kWh battery, and 12 x 330w PV panels.  My aim is generally to save Eskom costs, but also, to see me through load shedding. I am a novice user looking to learn more.
i have three questions. 
1. What are the recommended standard Axpert settings for this combo ? Current settings are:
01 - Sol  02 - 20a  03 - UPS  04 - SdS  05 - USE  06 - LtE  07 - ttE  09 - 50hz  11 - 20a  12 - 51v  13 - 53v  16 - CS0 
18 - bOF  19 - ESP  20 - LON  22 - AOF  25 - FEN  26 - 54.8  27 - 53.8  28 - 51 G  29 - 48.0v  30 - ONE  31 - SbE 
32 - AVt  33 - EdS  34 - 54.8v  35 - 60  36 - 120  37 - 30d  38 - d1 5  39 - AdS
Anything look amiss?
2. When loadshedding is frequent, and at night, the battery is running out as there is not sufficient time to recharge by Eskom.  At night the battery would normally power the house till about 11pm, run down to 20% and then Eskimo power would keep it at 20% and carry the load until sunlight.  I want this to be rather at around 35% to 40%.  What settings should I change to achieve this? (I have a second battery on order, arriving next week)
3.  Can a quality battery monitor be added to this system?  I have been reading about the disadvantages of using voltage level only to gauge battery level (as Axpert does) and was wondering whether a battery monitor would benefit me.