Problem with calc formulas

LibreOffice Version
Version: 4.4.0.3
Build ID: de093506bcdc5fafd9023ee680b8c60e3e0645d7
Locale: en_AU

PC details
Windows 7 Professional 64-bit SP1

Sample faults
A -Sheet name : ‘NUTRITIONS per Serve’.
correct =IF(OR( O12=0, Q12=0),BLANK, Q12/ F12)
Turns into ; =IF(OR( ‘NUTRITIONS per Serve’.O12=0, ‘NUTRITIONS per Serve’.Q12=0),BLANK, ‘NUTRITIONS per Serve’.Q12/ ‘NUTRITIONS per Serve’.F12)

B -Sheet name : ‘DAILY HEALTH SUMMARY’.
correct =VLOOKUP( $B38, 'DAILY_HEALTH,H$3,0)
Turns into ; =VLOOKUP( ‘DAILY HEALTH SUMMARY’.$B38,DAILY_HEALTH, ‘DAILY HEALTH SUMMARY’.H$3,0)

C -Sheet name ; ‘ACTUAL SHOPPING’.
correct =+IF(LEFT( $B27)= $B$4,VLOOKUP( $B27,STANDARD_ITEMS, F$4,0),BLANK)
Turns into ; =+IF(LEFT( ‘ACTUAL SHOPPING’.$B27)= ‘ACTUAL SHOPPING’.$B$4,VLOOKUP( ‘ACTUAL SHOPPING’.$B27,STANDARD_ITEMS, ‘ACTUAL SHOPPING’.F$4,0),BLANK)

Above shows continual automatic changes made to my formulas.
This happens to ALL sheets (17) in my workbook.

The sheet names were not entered by me and confuse me.
When I remove them Calc re-introduces them. Why?

Is there a setting I’ve missed?
Thanks John