But none of that is any sort of modification. If you feel it is, then you should inform the insurer if you change from, say, or from Dunlop to Falken tyres,
Now back when we had all that snow last december I did recall hearing that some insurers voided peoples policies for fitting non-standard specification snow tyres.
I would be very interested to learn more details about this because we are part of the EU now and some countries in the EU mandate winter tyres during Winter. My son, who has an Audi A4 which is registered and used in the UK but who spends a lot of time in Germany with his work is required by German law to have Winter tyres. It's hard to see how any insurance company could void a policy because an owner decided to comply with the law. You will find that, somewhere in the Mini's homologation paperwork there will be an approved size and specification for Winter tyres. No European insurer can ignore EU rules and if a policy has been voided in writing by a UK insurer due to the car having properly fitted correct size Winter tyres the European Commission should be informed as they will have a serious point of view.
And, yes, I do know what I'm talking about here as some years ago I had to report a German organisation for applying their own rules as being above EU regulations. The German organisation had to alter their rules.
I have to say, this thread is a lot of nonsense as water hoses, ignition leads and the colour of the paint on the block are not alterations or modifications in the sense the insurance company mean. By 'cosmetic appearance' they mean things like spoilers and air dams, ultra-wide wheel arch extensions, bonnet scoops, body kits and similar mods.
Of course lowered suspension, wider wheels, different brakes, different head, cam, carb(s), manifolds, exhaust systems, seats, seat belts, a roll-cage, white competition number squares on the doors (with or without numbers), suspension arms, fibreglass body panels, etc, are modifications are all modifications and should be declared.
The problem the insurance companies have with an old vehicle like the Mini is obtaining a definitive specification of what is standard on a specific model. For example,m even after years with Minis I could not get a definitive answer as to what the standard cam was as fitted to a 1990 Cooper 1275. I also got conflicting answers as to inlet valve sizes for the same car.
Say, for example, you have a Mini without wheel arch extensions. How would an insurer know whether they were or were not fitted as standard? Some models had them and some didn't.
Refusal to pay out will happen when highly visible alterations are not declared. It is unimaginable that an assessor would recommend non-payment of a claim because the cylinder block was black and not red, or the steel rocker cover was painted silver not green. Mini engines have been green, silver, gold, black, red and yellow over the last 50 years.