Finally understood... and yet I wanted to solve the problem by formula rather than VBA
I think I've done
Ctrl+Shift+Enter NOT just Enter
B1 =MID(A1,MAX(1,MIN(IFERROR(SEARCH(" "&TEXT(--MID(A1,ROW($1:$55),4),"0000")&"m"," "&A1),9^9))),4)
[TABLE="width: 446"]
<tbody>[TR]
[TD][/TD]
[TD]A[/TD]
[TD]B[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]XC-163 1227m Timber problems 0425m[/TD]
[TD]1227[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]0600m failed picture cv-76[/TD]
[TD]0600[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]ligts out 0987m p3[/TD]
[TD]0987[/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD]some other text 0123m[/TD]
[TD]0123[/TD]
[/TR]
[TR]
[TD]5[/TD]
[TD]from 3em now to 3752m and after[/TD]
[TD]3752[/TD]
[/TR]
[TR]
[TD]6[/TD]
[TD]frohm 3453m 4m to 0750m and after[/TD]
[TD]3453[/TD]
[/TR]
[TR]
[TD]7[/TD]
[TD]from 5m now to 1750m and after[/TD]
[TD]1750[/TD]
[/TR]
[TR]
[TD]8[/TD]
[TD]r 0523m 4m to 0750m and after[/TD]
[TD]0523[/TD]
[/TR]
[TR]
[TD]9[/TD]
[TD]XC-163 1227m Timber problems 0425m[/TD]
[TD]1227[/TD]
[/TR]
[TR]
[TD]10[/TD]
[TD]XC-163 237m Timber problems 0425m[/TD]
[TD]0425[/TD]
[/TR]
[TR]
[TD]11[/TD]
[TD]XC-163 234527m Timber problems 0425m[/TD]
[TD]0425[/TD]
[/TR]
[TR]
[TD]12[/TD]
[TD]XC-163 dream 34527m Timber problems 0425m[/TD]
[TD]0425[/TD]
[/TR]
[TR]
[TD]13[/TD]
[TD]This is a dream 4m to 0750m and after[/TD]
[TD]0750[/TD]
[/TR]
[TR]
[TD]14[/TD]
[TD]1600m failed picture cv-76[/TD]
[TD]1600[/TD]
[/TR]
</tbody>[/TABLE]