£5 Polymer UK Note / Coin Collector , I Need Assistance

Hey!

Im new here so guy easy ladies and gents . x

Right i'll cut to the chase ;
I + My Father , Have been collecting coins (mainly UK ) for quite some time now And have now moved onto Notes(ish)

Obviously , yeah the £5 boom or whatever .
Managed to eventually get a AK47 in circulation new condition ,
Had a wedge of AA01 variants , Although;
We have just been laiden with an AA01 366663 - So within the first 500K.

Any thoughts ? Worth selling or what not ?

Also coins wise , a cohort of different 50p , the odd random jersey guernsey 20p . And a shed load of £2 different designs also ?

Other than ' ebay' (as it can be misleading ) where do I start as to rarity/collecting value?

All help / comments welcome .
Thank you ,

Lewey.