65% is what you would expect to get get allowed on a car. This is because loads of people claim for a car that they don't really use that much for business.
For a van it should be more like 90% or even 95%. I negotiated 95% on my van because we also have a car and the van is converted with a tank in it so its a specialist vehicle and can't be used for any of the normal functions you would expect a van to be used for as private use like taking rubbish to the dump etc.
Also its only a two seater and as we are a family of four its not capable of transporting the family.
I think you accountant is being a bit lazy about this, it is her job to negotiate it for you. Thats what you pay an accountant to do.
Also, I don't think travelling to your first job counts as private use, its only if you are travelling to a permanent place of work that its classed as private. You are transporting materials and personnel for the purpose of your business so its not private use. Also, if your van has a tank etc its a specialist vehicle and that counts for a lot.
Accountants have to push for these things on your behalf. Almost anything can be negotiated with the Revenue provided you have a genuine case and aren't just trying to pull a flanker.
If you are not getting what you want off this accountant talk to another one. Talk to several, if this accountant can't be bothered to negotiate this for you the chances are there are other things that are not getting claimed for as well.