Most good classic insurers will be ok with your valuation, as long as you're within the range they already insure. Peter James for example will let you self-certify if it's over 20 years old & under £15k - there have been problems with certain other insurers though! Peter James insure loads of Pandas though, so they will know the correct values already.
A formal valuation can be done if necessary, though you would need to be a member. The valuer usually wants to see the car though, which may cause issues depending on where you are.
Unfortunately it's not a car I know personally & I haven't seen you at a show - I would personally be willing to value a Panda based on detailed photos (it's quite easy with Pandas, I know what they are worth depending on the condition), but it would really depend on exactly what the insurer needs. If it's got to be a formal valuation to stand up in court, then I wouldn't tread on the valuer's toes as he does the official valuations (to be honest, I'll tell him what I think in the case of a Panda anyway!). If a confirmation by email from a Fiat Motor Club official is ok, then I can do that easily.
Who is the insurer, what have they asked for, and (quite importantly) what did you give as a value? PM me if you don't want to spread it around the forum! Tbh it doesn't matter what you've told them, the standard Panda valuations are pretty set in stone, and you're not going to sway me away from it easily.
