I understand that raspberry however how do we judge what is the fair amount for any of it when we are not giving specific of what they are claiming for?
You don't have to, the adjudicator will decide based on evidence from the landlord. They will be asked to provide evidence of damage, and proof of the age/cost of the item (receipts etc), then you will be given the chance to dispute it. It is best at that point that you get your own quotes/evidence, if you disagree.
Is there a check in and check in report? Do they have photos on them? Ideally you should have taken your own photos.
Chip on the cooker - they can't charge you for a new cooker, only the cost of repairing the chip. However, it might be considered to be fair wear and tear. Even if it were broken, they can only charge you a pro rata percentage of the cost of replacement based on the age of the cooker compared to the average life of a cooker of that quality. This is a guide to how the TDS calculates the value and lifespans:
www.tenancydepositscheme.com/wp-content/uploads/2021/04/A_Guide_to_product_lifespans.pdf
Carpet - they will need to show its condition when you moved in(inventory), the cost, quality (different quality carpets have different life expectancies) and age. However, if the step can't be repaired separately or matched, you may have to pay for the whole carpet (pro rata).
The garden - they will need to give more detail. You should have left it in the same condition as when you moved in ie no weeds, lawn mowed and any small hedges/shrubs should have been regularly pruned but if it wasn't the appropriate time of year for pruning, you don't have to prune them before you leave. Trees and very tall hedges are the landlord's responsibility.
The mat and the shelf are your word against the landlord if there are no photos. Realistically, if neither of you have any photographic evidence and the number of shelves isn't noted, you would probably win with the shelf. If the 2 mats are listed in the inventory, you may be found liable if it is really missing and you have no proof you left it. I would ask them to check again and tell them where exactly where it was left (in case the clerk missed it). If there were workmen or viewings at the property after you left and before the move out check was done, I would raise that, as they may have moved/taken items.