Colour Shemes – can one lot in a strata of three change thier colours?

I own a 1920’s house (lot 1) on a block in PerthWA, that was subdivided into three lots in the mid 90’s. The strata bore reticulation is run from our meter. Although Lot one is very different in style to Lots 2 and 3, we all share the same colour, dark green guttering and doors. All strata fencing is light grey, unpainted fibro in varying states of repair.

All properties are detached – except for our garden shed, which was built as part of the structure on the side of Lot 2, Lot 2 building forms the bottom boundary to our garden so is a shared strata wall. 

There is no active Strata Company covering these three lots and therefore no levies to cover maintenance. Over the last six years of ownership, the owners of lot 3 and I have maintained the communal areas and gardens and when decorating the exterior of our properties we have done our own work without seeking payment from the other lots.  The ownership of lot 2 changed three years ago and is an investment property. Lot2  have not contributed to the physical or financial upkeep of the communal areas, including the cost of running the reticulation nor have we sought payment.

Lot2 have now introduced themselves, and advised that they are about to commence decorative works to their property and will be either replacing or repainting the gutters in a dark grey.  As part of the guttering is within our strata, they have asked us for a small contribution.  I understand that legally we are obliged to contribute our share (as are they to to the overall upkeep of the strata).  They have not sought our permission or opinion over the change the colour of their lot as they believe it is their right to do make changes within thier boundary.  We have asked for colour charts so that we can have a look at their proposition. They have declined to provide these.   As the 3 metres of gutter plus a down pipe is within our garden and is green, and as our shed door is green, and all the lots are green, are they entitled to change the colour without our agreement?

They have also stated that they intend to paint the fibro fences nearest to their lot – part of which are strata (and all of which are visible within the communal area), but they do not wish to paint all the fences on the strata (some of which are bore stained) – just those nearest to their lot (which are relatively new). They of course would like a small contribution toward this too. They are planning to use a professional company and claim that as a ten year warranty is offered, it would absolve them of ongoing maintenance for the painted work over the next ten years! We are of the view that as the fences do not require painting, and that painting them would attract graffiti – which would not be covered by the warranty and would  require all three lots to continue to spend on repair work. 

Where do we stand?  Can they change the colour scheme on their lot – especially as part of their lot forms our boundary. Can they paint the outside of strata fences without the agreement of all the lots and furthermore then expect us to pay.  If they get agreement can we then enforce that either all are painted or none are painted, and that regardless of warranty, they will remain equally liable for the upkeep at all times?

Thank you in advance for any advice you might give