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 ( APO )

last year.

($1 = 0.7836 pounds)