Holding(s) in Company

For filings with the FCA include the annex

For filings with issuer exclude the annex

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES i

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached: ii

Horizon Discovery

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

No

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

No

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

No

An event changing the breakdown of voting rights

No

Other (please specify):

Transaction in own shares

Yes

3. Full name of person(s) subject to the notification obligation: iii

Invesco Limited

4. Full name of shareholder(s)

(if different from 3.): iv

5. Date of the transaction and date on which the threshold is crossed or reached: v

9 January 2015

6. Date on which issuer notified:

12 January 2015

7. Threshold(s) that is/are crossed or

reached: vi, vii

5%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

Ordinary Shares

GB00BK8FL363

3,975,000

3,975,000

3,975,000

4.98%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/ConversionPeriod xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exerciseprice

Expirationdate xvii

Exercise/Conversionperiod xviii

Number of votingrights instrumentrefers to

% of voting rights xix, xx

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

 3,975,000

 4.98%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable: xxi

Proxy Voting:

10. Name of the proxy holder:

11. Number of voting rights proxy holder will cease to hold:

12. Date on which proxy holder will cease to hold voting rights:

13. Additional information:

14. Contact name:

15. Contact telephone number:

Note: Annex should only be submitted to the FCA not the issuer

Annex: Notification of major interests in shares xxii

A: Identity of the persons or legal entity subject to the notification obligation

Full name

(including legal form of legal entities)

Contact address

(registered office for legal entities)

Phone number & email

Other useful information

(at least legal representative for legal persons)

B: Identity of the notifier, if applicable

Full name

Invesco (UK) Limited

Contact address

Perpetual Park, Perpetual Drive, Henley-on-Thames, Oxon, RG9 1HH

Phone number & email

01491417000

Other useful information

(e.g. functional relationship with the person or legal entity subject to the notification obligation)

C: Additional information

For notes on how to complete form TR-1 please see the FCA website.