LibreOffice 4.2.0.2 - "Block position not found" - Critical Crash

[Jim Cobley]

I have just started receiving this crash on 14.04
Caused with a large workbook with several sheets and quite a few links 
and doing a Menu -> Insert Row
Calc crashes with the message dialogue "Block position not found" and 
closes down

I can't provide the spreadsheet for testing as it contains a lot of 
sensitive info and so far I haven't been able to remove that info and 
end up with a version that still crashes.
I have been using the spreadsheet successfully under Excel and LO 
4.1.4.2 on Debian

I assume that this is a new RC release?