Gillian purchased 10,000 ordinary shares in Downtown plc in January 2018 for £20,000.

In October 2023, Upmarket plc acquired the whole of the share capital of Downtown plc following a takeover bid. The terms of the take-over offer were:
One ordinary share and two preference shares in Upmarket plc, plus £3 cash for every five shares held in Downtown plc. The share prices of Upmarket plc immediately after the takeover were:
Ordinary shares £10 each and Preference shares £3 each.
You are required to:
Calculate Gillian's chargeable gain arising in 2023-24.