[GNC] Error Message on trying to Open a gnucash file "There was an error parsing the file...."

[Francis Greaves]

I am trying to open my accounts files from earlier this month. 
I am using an up to date Gentoo Linux, and had GnuCash version 2.7.4 installed. 
I am getting a message: There was an error parsing the file <Path/To/FileName.gnucash> 
I can open some old files going back 5 years, but not the recent ones. 
So I have downloaded and built GnuCash version 3.1 from github, but get the same error. 

When I try and open a file from the command line I have this output:- 

<gnc:transaction version="2.0.0"> 
<trn:id type="guid">bf0dc41716415d9f0959d27fe53fee5c</trn:id> 
<trn:currency> 
<cmdty:space>CURRENCY</cmdty:space> 
<cmdty:id>GBP</cmdty:id> 
</trn:currency> 
<trn:date-entered> 
<ts:date>2009-09-24 15:19:05 +0000</ts:date> 
</trn:date-entered> 
<trn:description/> 
<trn:splits> 
<trn:split> 
<split:id type="guid">936968474430cb3f7e1744100fa3f75c</split:id> 
<split:reconciled-state>n</split:reconciled-state> 
<split:value>0/100</split:value> 
<split:quantity>0/100</split:quantity> 
<split:account type="guid">66417896cab27b4aa27a6f0d6b8d48e8</split:account> 
</trn:split> 
</trn:splits> 
</gnc:transaction> 

Does anyone know how I can either 'repair' the file or get it to load? 

Regards 
Francis