Its definitely a slime mould Ric. They are an amazing lifeform. They exist in organic matter as single organisms or small communal organisms, but when conditions are right they join together to produce
zoospores. Kinda like mobile seeds. These are primarily produced when there is enough soil moisture for the zoospores to move through the soil and spread.
There are many types of slime mould (ignore the americanization of the name there is a 'u' in it.
) and some have amazing colours.