langou

Don't complicate stuff too much - getting the sizing 100% right before you start is less important than it used to be if you select your equipment to be scale-able.
Inverter/charger: Rarely seen a Victron 3kVA Multi not doing the job from a power delivery point of view for the basics i.e. lights, gates, security, entertainment, even the occasional biggie such as hair dryer, kettle or microwave. Make sure your inverter is a true hybrid (can mix power sources) and bi-directional (feed power to both ACin and ACout) - Victron and Goodwe are good quality examples. If Victron - can expand in future by adding another 3kVA in parallel or go for 5kVA from start. If GoodWe - go for 4.6ES since they can't parallel and you sort of stuck with what you start with (is however quite big and competent and good for most homes - can also operate in grid-tie mode i.e. don't need batteries from day 1.
Batteries: W.r.t. batteries my opinion is to not even consider lead acid! - constrained in increasing of battery bank, easily killed, short life span, requires lots of space, plenty round trip losses, etc, etc, etc..... Pylontech offers good value LiFePo4 and is very scale-able. Revov offers even better value but less scale-able due to bigger chunks - 10kWh vs Pylontech's 2.4kWh.
PV: Start with array of 8 x 330w Tier 1 Poly's and get some data on system performance before taking next step - you can always add.
PS - use a competent installer that have good references! Good components is not the only ingredient for a good system... 

Gener-8 Pretoria East (email [email protected]) also does PylonTech but prefer to part with them as part of high quality Victron systems rather than DIY sales. Recently PTs been scarce as chicken molars so maybe that's why such poor response from suppliers....been easing up lately due to pre-election window dressing but suspect Prince of Darkness to frequent us again in the (very) near future prompting renewed run on stock! If you've been teetering on the edge of commitment, now might be a prudent time to take the plunge...

Also use them with happiness!! Try ElctroMechanica online store - has big Hager selection.