pre_text: 15 Goodwill and other intangible assets continued Acquired intangibles The disclosure by class of acquired intangible assets is shown in the tables below. 2019 Customer relationships are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. Within this balance individually material balances relate to Thermocoax £32.6m. The remaining amortisation period is 14.3 years. Brand names and trademark assets are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. Within this balance individually material balances relate to Chromalox £114.1m (2018: £125.4m), Gestra £28.4m (2018: £32.5m) and Thermocoax £13.6m. The remaining amortisation periods are 17.5 years, 12.3 years and 19.3 years respectively. Manufacturing designs and core technology are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. Within this balance individually material balances relate to Chromalox £12.9m (2018: £15.1m), Gestra £10.8m (2018: £12.3m) and Aflex £8.5m (2018: £9.4m). The remaining amortisation period is 12.5 years for Chromalox, 12.3 years for Gestra and 10 years for Aflex. Non-compete undertakings are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. There are no individually material items within this balance.
table: Customer relationships Brand names and trademarks Manufacturing designs and core technology Non-compete undertakings and other Total acquired intangibles
table: £m £m £m £m £m
table: Cost:
table: At 1st January 2019 57.1 187.3 56.0 20.2 320.6
table: Exchange and other adjustments (3.0) (7.8) (2.2) (0.9) (13.9)
table: 54.1 179.5 53.8 19.3 306.7
table: Acquisitions 34.9 14.3 7.2 3.8 60.2
table: At 31st December 2019 89.0 193.8 61.0 23.1 366.9
table: Amortisation and impairment:
table: At 1st January 2019 25.1 21.3 14.2 15.6 76.2
table: Exchange adjustments (1.3) (1.1) (0.6) (0.8) (3.8)
table: 23.8 20.2 13.6 14.8 72.4
table: Amortisation and impairment 7.1 10.4 5.6 3.7 26.8
table: At 31st December 2019 30.9 30.6 19.2 18.5 99.2
table: Net book value:
table: At 31st December 2019 58.1 163.2 41.8 4.6 267.7
question: Analyse this data from a financial earnings document. What was the change in the amount of individually material balances under manufacturing designs and core technology for Aflex in 2019 from 2018?