What happens if i declare my car as sorn?

It depends on the policies of the new insurance company, though I have not encountered one that does less than 2 years.

The important thing is to get proof of no-claims bonus. Usually your renewal notice will state how much NCB you have but some do not, in which case contact the insurer and ask them to send you one. It's worth contacting them anyway to make sure that they do not auto renew using stored card or DD details.

One thing to consider, depending on where you live, is that you wont be covered for fire or theft. You may want to consider a "lay up" policy for the 3 months.

Find your cheapest MOT station, some are £35 they can be found for £20 in some rare cases.

Get it MOT'd to find out exactly what the score is - repair costs - so you know what you have to save up for.

It may not be worth keeping this car. Might be more economical to scrap it for £80 - £150 (money paid to you to scrap it), Use the money towards another old car with a full MOT, maybe costing £300 - £500.

Keep your old car until you have the new car.

When you SORN/SELL/SCRAP expect a letter from DVLA after 3 - 4 weeks, keep this letter safe with your car documents for at least 2 years even if you do subsequently re tax/sell/scrap the vehicle. If no letter phone DVLA after 3 weeks of declaring SORN.

If keeping the vehicle off road, make sure tyres pumped up higher than normal, every 3 weeks to a month move the car about 8 inches - this to stop your tyres becoming distorted in one place. If possible start the car every 3 weeks and allow the engine to warm up a bit. If the battery goes flat invest in a battery charger. A long period of non use non starting can kill a battery, meaning more expense for you so best to avoid this by regular starting and charging.