422 - Unprocessable Entity while creating bank_transaction_explanation

Hi,

I received a 422 Unprocessable Entity when trying to create a bank
transaction explanation.

Could you please have a quick look to the json below and let me know what’s
wrong with it?

{“bank_transaction_explanation”:{“place_of_supply”:“France”,“bank_account”:“https://api.freeagent.com/v2/bank_accounts/260711",“dated_on”:“2016-05-17”,“description”:"Sale
(EUR 83.99 - Ref xxxxxxx -
FR)”,“gross_value”:65.35,“category”:“https://api.freeagent.com/v2/categories/002",“ec_status”:"EC
VAT MOSS”,“sales_tax_rate”:20.0028575510787,“marked_for_review”:true}}

I suspect the issue comes from the VAT rate (I used a double which was
represented as String with lots of digits).

Would it be possible to get the field details for this API call (length and
expected format)?

Thanks
Guillaume