I'm not sure exactly which 'value' it is that you're seeking. Unused stamps will have three values:
(a) the value at which they can be used when posting something ;
(b) the nominal Stanley Gibbons catalogue value ; and
(c) the value which they actually have if you sell them to a collector.
(The 'value' of a stamp shown in the Stanley Gibbons catalogue is the ridiculous price that they'll sell that stamp to a collector who's desperate enough to want to buy it from them. The price that they'd pay to buy such a stamp isn't normally more than 15% of the catalogue value, with stamps often changing hands between collectors at around a third to a half of the catalogue value).
If it's the value that the stamps are worth for posting items that you're after then, obviously, a 64p stamp is worth 64p. (However I think that you'll find that it's actually 65p). 1st and 2nd Class stamps retain their value as prices change, so those two stamps are currently worth 67p and 58p respectively. 'E' stamps were issued to cover postage of a letter (up to 20g) within Europe. So the current value of that stamp is £1.25.
The 'catalogue' values of your stamps can be found on the Stanley Gibbons website:
https://www.stanleygibbons.com/stamps/great-britain/
The more realistic 'trading' values can be estimated by taking a look on auction sites to see what they're being offered at. (Remember though that some sellers seek unrealistic prices, which nobody ever pays). eBay is, of course, the most well-known. e.g.
https://www.ebay.co.uk/itm/362330769365
However serious collectors are possibly more likely to use Delcampe:
https://www.delcampe.net/en_GB/collectables/stamps/great-britain/presentation-packs/great-britain-presentation-packs-definitive-packs-2002-scotland-2nd-65p-55-564881754.html