Ну вот похожее объявление, дают от 80к до 130к зелёных президентов в год. Это в Дублине. В Лондоне соответственно должны давать больше. А так как контракт, а не нормальная работа - то ещё больше.

отсюда

Key requirements:
• Outstanding programming skills in C++, C#, or Java
• 3+ years experience designing, implementing, and shipping complex applications
• Great blend of technology background, passion to learn, and customer focus
• Energy and desire to deliver high-quality software on aggressive schedules (minor releases every 3-6 months, major releases within 12-18 months)
• Proven record of shipping on time and at a very high quality level.
• Strong English verbal and written communication skills.
• A university computer science degree or equivalent (master’s or PhD degree would be a plus)
• Experience with agile development methodologies would be a plus.

* Location: Dublin, Ireland
* Compensation: Compensation: remuneration package of $80k to $130k negotiable and including base salary, bonus, health plan, on hire stocks, and generous pension contribution