Not that it matters a jot, but it’s not that they are different prices. 40p or 50p shares can be sold for £100 each or 1p each depending on the value of the company, the 40p or 50p is just a nominal value.
They are different classes, with the 40p shares having been created by special resolution on 22/10/20. They rank pari passu in all respects per the Articles of Association, so it’s academic though - neither class ranks above the other.
ETA - document freely available on Companies House, page 3, para 2.1.