July 3 (Reuters) - Dubai-based engineering and consulting firm Sidara has sought the extension of a deadline to make a firm offer for UK's John Wood Group to July 31, after being rejected thrice earlier.

Sidara, previously known as Dar Al-Handasah, approached the British oilfield services and engineering company three times across May and June, taking the offer from 205 pence to 230 pence, which it had said would be its final offer.

The offers were rejected by Wood Group over valuation and future prospects concerns.

Sidara's latest offer values Wood Group at 1.56 billion pounds ($1.99 billion), representing a premium of 52% to its closing share price before the first bid was made.

The Scotland-based Wood Group had rejected a 240 pence apiece offer from U.S.- based Apollo Global Management last year. ($1 = 0.7836 pounds) (Reporting by Prerna Bedi and Unnamalai L in Bengaluru; Editing by Rashmi Aich and Shailesh Kuber)