Conditional Format using vlookup, indirect and table reference

[LocalManMark]

Hi All,

This is my first post so please be patient.

I have simplified what I want to achieve in the following example using kids building blocks of different sizes.

First I have a reference table called BlockTypes

[TABLE="class: grid, width: 500, align: center"]
<tbody>[TR]
[TD]Block[/TD]
[TD]Size[/TD]
[/TR]
[TR]
[TD]A[/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD]B[/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD]C[/TD]
[TD]2[/TD]
[/TR]
</tbody>[/TABLE]

I then have a table that lists the spaces and what block is in each space Table1
[TABLE="class: grid, width: 500, align: center"]
<tbody>[TR]
[TD]Space[/TD]
[TD]Block[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]A[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]B[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]C[/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]5[/TD]
[TD]A[/TD]
[/TR]
[TR]
[TD]6[/TD]
[TD]B[/TD]
[/TR]
[TR]
[TD]7[/TD]
[TD]C[/TD]
[/TR]
[TR]
[TD]8[/TD]
[TD][/TD]
[/TR]
</tbody>[/TABLE]

So the logic above is that because Space 3 contains a block of type C it takes up 2 spaces, Therefore nothing can go into Space 4. The same goes for Space 7 and 8. (I do hope I'm explaining this well .)


What I want to achieve: I want to create a conditional format to Fill the block cell for 4 and 8 black.

Formula's I have tested
Ideally I would like to use this formula as a conditional format

=NOT(ISERROR((VLOOKUP((INDIRECT(ADDRESS(ROW()-1,COLUMN()))),BlockTypes,2,FALSE)=2)))

This works as a cell formula but not as a "Conditional Format" Formula

The following simple fomula works but would be difficult to manage if more blocks with different sizes were introduced.

=INDIRECT(ADDRESS(ROW()-1,COLUMN()))="C"

Theory on Issue
I am wondering if this issue is to do with the reference to the Table "BlockTypes", but I can't see any other way around it.

Hope someone can understand my question and help