1997, citroen berlingo 1997 1.9 diesel automatic . is this worth £10,000?

OMG if it's in good condition it's a collector's item!  It is worth GBP 50,000 pounds at least, will be more in the future!  But only if it's still in the original packaging.

Since it's a camper van it could be worth £2,000 in good condition, but never £10,000.

£500 max if it has at least 6 months MOT.

Nowhere near.... in 2014 it cost me £1600 for a 2002 Ford Fiesta 1.3 that's probably worth about £500 now.

A Citroen van that's coming up to 22yrs old I'd say would only be worth about £350 on the basis that it's very old (most cars quit working completely after around 25yrs without major restoration work), and as it's French and very old for a vehicle the reliability will be very questionable..... anything French tends to go downhill very fast after about 5yrs old, and after about 10yrs old repairing them gets like painting the forth bridge.

I know of 2 people who had a Citroen Saxo (c. 10-12yrs ago) who got shot of them at 5-10yrs old because 1 year they had to fix a shedload of stuff to get it through the MOT test... then the following year's MOT the things that needed fixing the previous year needed fixing again already.

It might be worth £700 - £850 if stripped down and sold for spares.

You'd be lucky to get 10,000 pence.

I hope you don't live anywhere near a Low Emission Zone. London has just declared war on old diesel engines.

No, about £2500

Let's put it this way. You're not the brightest star in the sky.

That's a terrible price. You need to do your homework. See link for a typical example.

A 20+ year old Citroen for £10K? Not unless this was driven out of the showroom and straight into a climate controlled garage for storage.