Bricks with Impressed Heart Marks

I picked up a few different bricks from a neighbour last week to add to my collection.  Yes, I also collect bricks and also garden edge tiles.  Haven't got a huge collection of each but I like to pick the odd ones up when I can.  I suppose my brick collection began over 30 years ago when we bought 5 tip truck loads of bricks from the then demolished Virginia Pipe Works to use as paving around our home.  Of course there happened to be many different impressed frog marks amongst the 6,000 or so old bricks which meant I had to keep aside examples of each of the earlier ones.  Couldn't help myself.  Hence my brick collection was born.

Anyway, below is a photo of two bricks with impressed hearts in them.  One with a single heart and one with two hearts.  I would love to know where they were made.  My guess is that they are of Queensland origin but don't have a clue to their age or which brickworks they come from.  Please feel free to leave a comment if you know any information about them.

The next two bricks also came from my neighbour.  I am sure that the 'Q' stands for Queensland but have no idea which brickworks it comes from.  The other brick has 'W' (or maybe an 'M')  impressed into the frog (the indentation in the face of a brick).  Any information about any of these bricks would be most appreciated.

I will put some of my other bricks and garden edge tiles on a future post.