Small Claim Not Appropriate for Money Claims Online?

[Obuscurantist]

I have issued a Small Claim via Money Claims Online. The Defendant is unrepresented but has either phoned or emailed the Court complaining that the Claim is unreasonable. The Court has received no application to strike out but the clerk referred the Claim form to a district judge. The claim is for a specified sum, but the clerk suggested it might be unsuitable for MCOL and might therefore be struck out with guidance to re-file via CCMCC.

Is this correct and is it a common process?