Double interpolation of table?

[timberscombe]

Hi Mr. Excel Forum - I'm wondering if anyone can help me please? I'm pulling out what little hair I have left in my head!

Basically I have a table of results and I am trying to use Excel to calculate the exact value I need by a means of double interpolation of this table.
I have read a few posts on here with people having similar queries but this is slightly different from those I've read so far....

I'm not sure how this extract from my table will appear once I have uploaded this thread, apologies if it is a mess, but here is a sample of the table that I'm looking to interpolate:

5 10 15 20
180 221 166 133 112
185 219 163 130 109
190 217 161 127 107
195 215 158 125 104
200 213 156 122 102
210 209 151 118 98
220 206 147 114 94

The values along the top (5,10,15,20) are relating to values of dx
The values along the side (180,185,190,195,200,210,220) are LE values

For arguements sake, say I have calculated a value of dx = 12.8
and a value for LE = 196.2

Is there anyway I can get Excel to work out what is the correct corresponding value from the table.

Thank you for taking the time to read this, any assistance will be greatly appreciated.