Just noticed this account offering interest rates from 3.5% up to £9,999 and 3.85% for currency over £50,000.

more on Nationwide's 3 year e-Bond:
3 year e-Bond (annual interest) savings interest rates and account summary from Nationwide Building Society


£1 - £9,999 3.50 n/a 3.50 2.80
£10,000 - £24,999 3.55 n/a 3.55 2.84
£25,000 - £49,999 3.65 n/a 3.65 2.92
£50,000 - £3,000,000 3.85 n/a 3.85 3.08