Pretty simple. My right hand (pectrum plucked) has a lot of inconsistency.
I have been practising using a 50bpm metronome, alternate picking, 3's, 4's etc and increasing the pace of the metronome.
Is this correct?
When I sit and record on Audacity, inconsistencies are clearly audible.

Please advice

It depends what you mean by inconsistencies. Timing errors? Fluffed notes? Difference in volume? Difference in attack?

Either way if you are starting at 50bpm and speeding up the metronome, is it apparent at 50bpm or does it start to occur at 60? 70? If so, you're speeding up the tempo before you're ready to move on.

Finally, what magnitude are these inconsistencies? I've done many recording sessions where the bass performance sounds strong and very musical in the mix but has what you might call inconsistencies when the engineer hits the solo button. They're very slight, things like a little finger noise become apparent and, when soloed, even intentional things like dead notes can sound like a fluff when listened to out of context - it happens to us all, even those of us who play with fingers ;)

It may be that the inconsistencies you describe are too minor to be material, but only you can calibrate your self criticality

Mainly its timing errors between an upstroke and downstroke, when i am playing 3's, 4's etc, which sound ok with the bass/kick drum and guitars but bad when they are soloed.

Also mainly shifting fingers/playing the next note at 100 bpm alternate picking my right hand goes for a toss.

Any exercises I must practise?

Just keep at it. 50 bpm is tough for me as well. It is really slower than I want to mentally count. I found the exercises in Rufus Reid's "The Evolving Bassist" to be great for me. They break up the rhythm very well having you switch around a lot, and he sets the practice tempo at 50. I'm still a little weird at that slow a speed, but not nearly as bad as I was.