Bank Reconcillation suddenly showing old transactions

I have resolved this now - however I didn't need to undo two years worth of daily reconcilations to do so, based on the issue we had which was a relief!

Our Issue was this: Our current rec balanced, but we suddenly discovered many previously-reconciled transactions with old dates also showing, and should you tick them,  the bank rec will become un-balanced.  

In our case, all I needed to do was delete all the transactions that had suddenly appeared. This is because I found they were automated "double-ups" of transactions that had previously been reconciled.  I suspect this happened after changing my settings to "automatically reconcile transactions" a few days prior. Despite having bank feeds for our bank account, we actually manually enter our transactions.. Therefore, after I changed the settings things got doubled up. To check  your settings go to:   SetUp > Preferences > Banking >  "Auto-Approve bank transactions matched to MYOB transactions (system wide).   This box was accidently ticked causing the double ups to appear next time we tried to do a bank rec.

Deleting the transactions isn't for everyone's case -  it may only work if you can see that the transactions are on MYOB are actually double ups. Upon first looking into this, there were no double ups but they did eventually show up which is strange.

I hope this answer helps others out.