I've created a excel based tool with various charts feeding from tables with
V-lookups which point towards a tab with base data in it.

Basically i've created one more table with similar Vlookup's to some
existing tables and now i've got the 'calculation shopwing on the grey bar at
the bottom of the screen and every click causes all the cells to be calucated
which freezes the spreadsheet.

I've also found that the charts aren;t working properly at this point as well.

Is this because i've got 2 vlookup's that are the same?

Is this linked to switching between manual and automatic calculation (via
Tools)? Although switching between the 2 isn;t helping.

Is it something else and if so what's the solution?

Thanks.