Am no expert but have claimed insurance from Scottish Provident, they were slow and did do some extra ( and nerve-wracking for me) following up with my GP and consultant as I had put an inconsistency about smoking on my claim form.
Your address makes no difference - I didn't even have original paperwork.
I told consultand we would be claiming they were happy to receive forms and said yes it is invasive - my staging was never made clear but think it was probably 1b1. The consultants are experienced at this so do contact them about it, they like to help I think.
if you feel you have a concern over the way the insurance company are treating you (or even just the speed of paying out) google 'financial ombudsman critical illness' and have a read, then mention them to your insurance company - I was about to do this but whenI called they said they would pay.
i also googled 'solicitor critical illness' and got some helpful tips from solicitors, who kindly gave me advice about my claim at the point where the insureNce company had a query.
I was clear of cancer at the time of my claim, the insurance is not dependant on you being horribly affected but on your cancer having fitted the criteria.