Snapraid. 1 Data Disk Broken. Following instructions but can't mount new disk, mergerfs?

I have 6 disks configured with snapraid and mergerfs. Finally had a replacement disk delivered and have plugged in. Foloowing the pdf snapraid document from the forum and got to Step 5 which is to Wipe the Disk (done!). The create a new partition via OMV > Storage > File Systems. Accessing this menu fails with

500 - Internal Server Error

Couldn't extract an UUID from the provided path 'src/UUID'

When I look at /srv from the terminal it seems that the UUID is from using mergerfs. Mergerfs is configured with the 4 data disks which one is now missing on an RMA.

I thought I might be able to delete the MergerFS by highlighting it in the web admin but the delete icon is greyed and unavailable

How can I get pass this to mount the device (per Step 5e from the pdf)?

Damn - in my fit of desperation, I googled and found that you can't delete referenced shares etc. So I deleted all the shares that was used by NFS and SMB. Then that allowed me to deleted the 'Shared Folders' under Storage. This then allows the Storage > File Systems menu to load up and allow me to mount the new drive.

Could have saved me time to try your easier method as I now have a ton of shares to recreate with their respective permissions and settings.

Now just waiting for the drive to be fixed by Snapraid now. Kicked it off via the web ui.

DO you know where the log file for the progress is that is shown in the window of the Web UI? Its gonna take ages and I like to turn off the desktop machine which access the web ui. How else can I check progress?

And to answer my own question (and for future reference for anyone with the same problem) - having had a google. To view the output of the web ui - found the answer here

SnapRAID Status after closing GUI

Hi, So I started a SnapRAID Sync in the OMV GUI and closed the browser tab. When I log in to the GUI and click SnapRAID Sync or Status, it...

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Under /tmp there is a bgoutput**** file, find the latest and I can tail it from a console.