Please forgive my ignorance donatkin, but what exactly are marms?
I've been very successful with marbled newts over the years and like to place two males with one female in the breeding tank. I have found that males make more of an effort if they have competition for the female. However, nothing is ever straightforward and I keep a keen eye on males interrupting what appears to be a successful courtship leading to spermatophore deposition and then uptake. I find it important that the substrate is suitable and there is room for the two animals with out interference from weeds etc. But even before we get to this stage, it is important that the adults have been 'prepared' through the year eg temperature cycle, feeding etc.