Hi basically coming to the closing stages of my polo conversion so sent the logbook off a few weeks ago with a receipt for evidence only for it too come back as the evidence being insufficient. Which is no biggy because I know of a garage I can have an inspection report made, however my insurance on my current car runs out in less than 2 weeks and no way is the logbook gonna be back by then.

So my question is could I tax the polo for its current engine and then insure it with all modifications declared and drive around? Or do the new changes need to be confirmed before any driving is done?

i'd speak to the insurance and insure it for the extra work done even if the log book isn't back. you'll deal with the dvla on their own for any tax increases

Thanks for the response but that's not really what I'm asking. The insurance is fine that's setup ready to go. But could I tax it for the old engine and start driving before the changes had come back? And possibly just pay the difference?

the dvla will calculate what you owe for the new tax bracket and take the price of the new tax you bought out of it sending a bill for the rest. or you can keep your car off the road till the log book come through.

Just looked at the DVLA tax website chart and according to that because the car is before 2001 and so is the engine I have put in surely the charge will be the same as before? So I could pay tax and there would be no change?

if you're still in the same bracket then all is as normal