SRV Failover with low PDD

FreeSWITCH Configuration
1

I am having issues with SRV and the XML Dialplan
I basically just want to have 2x SIP servers, primary and failover.
I want minimal PDD if the primary is down
My Config is as per below. If I take proxy1.domain.com offline and make a call, it is not even attempting send a call out proxy2.domain.com - let alone after 1-2 seconds

Perhaps my expectations are incorrect. Can I please get some advise on how to achieve auto failover to a backup proxy when a timeout occurs, and if possible through the use of SRV.

<gateway name="outbound-routing">
    <param name="proxy" value="proxy.domain.com"/> 
    <param name="register" value="false"/>
    <param name="ping" value="60"/>
    <param name="register-transport" value="tcp"/> 
    <param name="caller-id-in-from" value="true"/>
</gateway>

‘proxy.domain.com’

dig SRV _SIP._TCP.proxy.domain.com
_SIP._TCP.proxy.domain.com. 600 IN SRV 10 50 5060 proxy1.domain.com.
_SIP._TCP.proxy.domain.com. 600 IN SRV 20 50 5060 proxy2.domain.com.

dialplan-outbound.xml

<extension name="outbound">
  <condition field="destination_number" expression="^dial\+?([1-9]\d{1,14})$" break="on-true"> <!-- E164 - Outbound -->
    <action application="set" data="originate_timeout=1"/>
    <action application="set" data="originate_retries=2"/>    
    <action application="bridge" data="sofia/gateway/outbound-routing/$1"/>
  </condition>
</extension>
2

via fs_cli what does it return when you issue the command sofia_dig proxy.domain.tld ?

3 
Preference          Weight       Transport            Port         Address
================================================================================
         1           0.200             tcp            5060      1.1.1.1
         2           0.200             tcp            5060      2.2.2.2

sres.c:2827 sres_send_dns_query() sres_send_dns_query(0x7f895c01edb0, 0x7f895c33d2e0) id=48171 SRV _sip._tcp.proxy.domain.com. (to [127.0.0.53]:53)
sres.c:3477 sres_resolver_receive() sres_resolver_receive(0x7f895c01edb0, 48) called
sres.c:3787 sres_create_record() ANSWER RR received _sip._tcp.proxy.domain.com. SRV IN 91 rdlen=38
sres.c:3787 sres_create_record() ANSWER RR received _sip._tcp.proxy.domain.com. SRV IN 91 rdlen=38
sres.c:3787 sres_create_record() ADDITIONAL RR received proxy1.domain.com.. A IN 91 rdlen=4
sres.c:3787 sres_create_record() ADDITIONAL RR received proxy2.domain.com.. A IN 91 rdlen=4
sres.c:3787 sres_create_record() ADDITIONAL RR received . OPT 65494? 0 rdlen=0

I do suspect sofia_dig may have a bug in it as occasionally I recieve

Preference          Weight       Transport            Port         Address
================================================================================
         1           0.200             tcp            5060      2.2.2.2
         2           0.200             tcp            5060      1.1.1.1