Which battery for a ladies' Cellini 6229?

[chellini]

Hello,

Please can someone tell me which battery I need for my ladies Cellini 6229. It is the Danaos in white gold and is about 25mm across.
The movement says 6620 on it.

I found a website which recommended the

SR 721 SW (1.55V)

but I bought it and it is slightly too wide to fit in the space!

I have a '321' battery I just took out of my Omega and it is too small and shallow for the space, to give you an idea.

I also have a battery at home marked 'A63' which is too wide, and also too deep, to give more of an idea.

Thanks for any help with this!

Kind regards

[kakocemo]

Battery is 362