How to edit product custom fields once added to cart???????

[ravsimple]

A re-occurring problem my customers are facing and I can't seem to find a solution for this:

1. A customer adds a product with many product custom fields to the cart
2. Customer is re-directed to the cart
3. Customer realises he has made a mistake with one of the custom fields
4. Customer clicks on the product to edit the custom fields
5. Only then to realise that all the custom fields have reset

There needs to be a way that the customer can edit the cart??

Please see my screenshot so you can understand.

Many thanks for your help in advance 

Rav

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