2SLS estimation with an endogenous categorical independent variable

The following model was estimated:

Linear regression                             Number of obs =     10,288
F(45, 10242)      =     118.71
Prob > F          =     0.0000
R-squared         =     0.3259
Root MSE          =     .58052


                    |               Robust
ljbot |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
------------------------+----------------------------------------------------------------
greens |  -.1290424   .0360989    -3.57   0.000    -.1998033   -.0582815
libdem |  -.0211495   .0314561    -0.67   0.501    -.0828096    .0405105
leftwing |  -.0418696   .0184481    -2.27   0.023    -.0780314   -.0057078
apolitical |   .0541413   .0161846     3.35   0.001     .0224163    .0858663
ukip |   .0143972    .037146     0.39   0.698    -.0584162    .0872106
bnp |   .3696505    .069015     5.36   0.000     .2343675    .5049335


Where ljbot indicates the log of overtime hours worked. The independent variables of interest, greens, libdem, leftwing, apolitical, ukip and bnp, are all dummy variables derived from a categorical variable indicating a respondent's political party support. Support for the conservative party acts as the reference group. (A number of controls were also included in the model).

I have found a suitable instrumental variable 'mfgirl' (a dummy variable where 1 = has female children, and 0 = has male children only).

I estimated

ivregress 2sls ljbot greens libdem (leftwing = mfgirl) apolitical ukip bnp, vce(robust)

(and included all controls)

Instrumental variables (2SLS) regression     Number of obs   =      8,712
Wald chi2(45)   =    4198.35
Prob > chi2     =     0.0000
R-squared       =     0.2495
Root MSE        =     .61392


                    |               Robust
ljbot |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]


           leftwing |  -.7397816   .2952977    -2.51   0.012    -1.318554   -.1610086
greens |  -.5214898   .1758845    -2.96   0.003    -.8662171   -.1767625
libdem |  -.3840828   .1594964    -2.41   0.016    -.6966899   -.0714757
apolitical |  -.3148761    .160717    -1.96   0.050    -.6298757    .0001235
ukip |  -.3700357   .1704412    -2.17   0.030    -.7040943   -.0359772
bnp |  -.0658923    .186908    -0.35   0.724    -.4322253    .3004406


Is it sufficient to place the instrument on leftwing only?

When I run

ivregress 2sls ljbot (greens libdem leftwing apolitical ukip bnp = mfgirl), vce(robust)

(Including all controls)