Cell returns â£0.00 instead of correct value

I posted a similar problem 4 years which I thought was SOLVED, However, I couldn't get it to run properly so I gave up. I have now retired and wanted to give it another go.
Background:
CELL A4 SHARE EPIC DOWNLOADED FROM THE INTERNET
CELL B4 CURRENT SHARE PRICE
CELL C4 HIGHEST SHARE PRICE
CELL D4 DATE OF THE HIGHEST SHARE PRICE ACHIEVED

I want to track a share price and when it achieved its highest price (I can't get past getting C4 to work, let alone D4 to hold the date of when it achieved it highest value.
The problem I have is the formula in C4 (Highest share price) returns £0.00 and not MAX of B4 or C4. i.e. £4.84.

Any help would be gratefully received.

Excel version 365.