In the UK, Say im 3 months into a years insurance policy on my car. Can I then change the vehicle to a motorbike if I decide to get one, assuming the insurance company also does bike insurance?

Please tell me if you know of any insurers that allow this.

Are their any problems or things i should look out for when doing this?

thxs

No.

You will need to cancel your car insurance and take out a new motorcycle policy.

Some insurers do offer "6-wheel" insurance, though (combined car and motorcycle policies).

the insurance company want the money for the rest of the insurance that was left to pay its £166 can they do this even though my bike getting stolen wasnt my fault. i dont think its fair that since my bike has got stolen and i have cancelled ive got to pay the rest of it

Yes they can – check the policy details as there is always no refund in the later months of a policy even if paid monthly

If somebody has a crash whilst riding a motorbike, does their insurer (or all insurance companies, for that matter) blame the rider regardless of who’s fault it was?

No, a motorcyclist is not automatically blamed for an accident. I t-boned a car when it made a left-hand turn in front of me. My bike was totaled and the guy’s auto insurance bought me a new bike.