Why not pay a Jeweler to value it for insurance purposes for you. will likely highlight which pieces are worth more etc? obviously what they value it at wont relate to what they would offer, but if they think its for insurance then at least you'd get a more realistic value.
Love a bit of Lego! last kit i got was the new 90th anniversary Castle and Spacecraft (homages to the classic 80s sets) apparently me spending to many £££s on Lego is a bad thing, but her spending on clothes, handbags and sooo many shoes is fine..... Lego is an investment!
Sadly we found when we wanted to get an extension that any trades people with any kind of recommendations are booked up a year ahead, although hopefully (for you) the economic downturn will have shortened those waits as people can't afford for work to be done. Best of luck with the build, will...
Ali surely, People might not have agreed with some of his things out of the ring, but in it he was head and shoulders above all others, in my humble opinion.