Spoke to a friend today that often travels in other vehicles not just his own and he takes his ramps everywhere with him, if he is visiting for instance he uses the ramps to put on the front door threashold for easy access to the house as well of putting his chair in the car, He swears by telescopic channel ramps there are various makes but At present he has 6 or 7 foot (he can’t remember specs) made by AIDAPT. He paid £80 on ebay but as prices vary from £80-£180 for the same ones he suggests checking your local Mobility shop as you should get them VAT free but he wasn’t offered that option online.
these are the Aidapt ones extended and bagged (stock photos)
Edit: just checked the email he sent me with above info he also says you may be able to get them free through your local council if they have a occupational therapy or similar department. He had permanent ramp and handrails fitted so couldn’t claim for his.