Travel insurance, pre existing conditions important?

[Notdoingthis]

I have purchased travel insurance but forgot to declare my husband's depression. I have tried phoning to add it (we haven't left yet), but the phones aren't working, I keep getting cut off. How important is it to declare this? It is for a single trip within Europe. Thanks

Can you not do it online? We have insurance with Staysure and you can just sign in and make changes. Insurance companies use any opportunity they can not to pay, so id want it changed.

I had to phone. Got through eventually. It added £30.