Can i claim input tax on childrens clothing?

Hello, i have just recently submitted a VAT return and recieved a sizeable repayment, as i submit my returns myself i'd just like to confirm a couple of things and make sure that i am calculating everything correctly, less there be any problems down the line. I sell childrens clothing, there is no input on the clothing as they are zero-rated, however recently we have switched to using Royal Mail Tracked delivery which charges VAT and some of the materials i use to alter the clothing, aswell as packing supplies used to deliver them i am also charged VAT on. Am i allowed to claim the input tax back on all these items even if the finished product is zero-rated? Thanks

Hi,
As you are making taxable supplies at the zero rate then you have a right to treat the VAT incurred as input tax as long as you meet the conditions below:
Introduction to input tax
Thank you.