Hi @paulblueandwhite ,

If custom postage is allowed for a certain category then it should appear on the listing. If you have example listings where the sellers have been able to use custom postage for the same category you are trying to list in then send them on to me and will have it checked.

Thank you,

Kat

Update:

received a reply from eBay customer service by email after contacting them on Live Chat  and they explained to me how to list items larger than 61 cm - medium parcel. All sorted out now. But thanks for your help.