Item with high value

[faeriesamanthafaerie]

Hi

i I have a couple of items to sell that have high value . They need to go special delivery which doesn’t cover anything above £150. 
Any ideas on how I can get the correct postage that gives me the correct cover?

I tried putting £1000 value which gives me more choices but when I bring price down it reverts back to normal Royal Mail parcel.

Thanks  

[**peaseblossom**]

eBay's Simple Delivery automatically covers the seller for up to £750, if that's high enough.