Thank you everyone for your input! The existing boards are approx 30 years old, and other than the fact that they appear to be untreated timber, there is no obvious reasons why they have decayed. Hence why I would like to make an informed decision when replacing them so it doesnt happen again (maybe treated pine?). The worst is on the corners of the house which are subject to the most wet weather. But the boards have decay all along the house. Which it seems in turn has allowed insects to attack. We had a building/pest inspection done prior to buying last year, and the report said rot and 'earwig attack' (seems strange?), and there was no evidence of any termite damage/activity. But there is (what I think is) excrement of some sort present. Have attached couole of photos if anyone can identify the excrement? Report also said subfloor ventilation was adequate. However I want to space the new boards/material as far apart as possible to allow good ventilation, while adhearing to fire safety regs. So I will contact the CFA regarding that info as recommended.

For the street appeal I’d get rid of some of the trees - at least trim them so you can see more of the front of the house. Then look to paint in a tone-on-tone set of colours with the weather board and brick in contrasting depths of colour. Greys, blues, creaming grey-beiges look modern and fresh. You could also choose a strong contrasting colour like dark red or bright green for your door to make entrance more obvious. For the extra room, agree that converting the garage would be most cost effective. Then spend a little money getting a carport designed to create visual interest for the front of the house. Good luck!

I have to agree it was the landscaping and the imbalance of the colours that I noticed. From your additional comment I am not sure how important it is to you, but if you don't get it right a different colour won't work any better than the existing one IMO, and if you are going to replace the windows probably do that first, the different proportions of cladding and glass will change the look too. Btw how high is the railing? I know of people who had to change their railings due not being compliant with modern building codes. If you are having work done on the front you might as well find out about that at the same time and update if necessary.

@Lizzy B all went smoothly. the most time consuming part was installing all the battens into the brick followed by corner ends. This was harder because I cladded not only the wall shown with the 3 windows but also the whole front of the house which includes multi steped recession into the front door meaning lots of internal ans external corners as you will see in this next photo. most people would usually just paint this recession to door area rather than clad it because of how fiddly it is and so many short cut boards but i decided if i was going to do it, I would do it all prroperly. it all still looks fantastic and as if i did it yesterday.