Handbrake not holding

[Airwolf]

Not had a chance to look into this yet as I’m not currently near the car but the handbrake is not holding. Was told the rear calipers got rebuilt last year during the build but unsure over the truth of this. What’s the likely causes of this and steps to investigate / fix

 

[Jake_rorx7]

Check if you can tension it on the handbrake adjustment bolt on the inside of the handbrake lever. Keep tightening it until it's not grabbing on the first click, but it is when you go any higher. I carried around my 10mm spanner for this and adjusted it a bit after each time driving it, so I could feel for it (I live near a big hill on my way back from work where I can test the exact bite point really easily).

Are your pads in good health?
Is one wheel grabbing or both? You can test this easiest with both wheels in the air.