My car was stood still for a month or so. l went to start it and the battery was flat so l replaced the battery (as it was old) and I've checked the fuses (under the dash and bonnet) all are fine. Yet l still have no power, not even the dashboard clock or interior light.

Check the battery, they can have a dropped plate right of the shelf brand new. Check the other end of your negative battery cable for a good connection. If these are good check power to the fuse box. If you have power there then you have a lot of work ahead of you with your Volt/Ohm meter.

maybe a fuseable link

fiat stands for fix it again tony l had an 850 spider