I've read the available documentation (particularly the travel example), and googled around, searched this forum, etc. Cannot find a bullet proof example of how to simply add a single field to partner and have it displayed.

Here's what I have:

__openerp__.py

{
    "name" : "NT3",
    "version" : "1.7",
    "author" : "Foo",
    "category" : "Generic Modules/Others",
    "website" : "http://www.example.com",
    "description": "Foo",
    "depends" : ["base"],
    "init_xml" : [],
    "update_xml" : ["nt2_view.xml"],
    "active": True,
    "installable": True
}

__init__.py:

import nt3

nt3.py:

from osv import osv, fields
from tools.translate import _

class res_partner(osv.osv):
    _inherit = 'res.partner'

    _columns = {
        'mycol': fields.char('MyCol', size=16, help='Foo'),
        }

res_partner()

nt2_view.xml:

<?xml version="1.0" encoding="utf-8"?>
<openerp>
     <data>

        <record id="view_partner_form" model="ir.ui.view">
            <field name="name">res.partner.form</field>
            <field name="model">res.partner</field>
            <field name="type">form</field>
            <field name="inherit_id" ref="base.view_partner_form" />
            <field name="arch" type="xml">
                <field name="email" position="after">
                    <field name="mycol" />
                </field>
            </field>
        </record>   

    </data>
</openerp>

I can see mycol gets added to the database, but get this error when accessing the view:

2013-04-08 13:33:13,163 5956 ERROR dev8 openerp.osv.orm: **Can't find field 'mycol' in the following view parts composing the view of object model 'res.partner':
 * res.partner.form**

Either you wrongly customized this view, or some modules bringing those views are not compatible with your current data model
2013-04-08 13:33:13,163 5956 ERROR dev8 openerp.netsvc: View error
Can't find field 'mycol' in the following view parts composing the view of object model 'res.partner':
 * res.partner.form

Either you wrongly customized this view, or some modules bringing those views are not compatible with your current data model
Traceback (most recent call last):
  File "C:\Program Files (x86)\OpenERP 7.0-20130407-232401\Server\server\.\openerp\netsvc.py", line 293, in dispatch_rpc
  File "C:\Program Files (x86)\OpenERP 7.0-20130407-232401\Server\server\.\openerp\service\web_services.py", line 626, in dispatch
  File "C:\Program Files (x86)\OpenERP 7.0-20130407-232401\Server\server\.\openerp\osv\osv.py", line 188, in execute_kw
  File "C:\Program Files (x86)\OpenERP 7.0-20130407-232401\Server\server\.\openerp\osv\osv.py", line 144, in wrapper
except_osv: ('View error', u"Can't find field 'mycol' in the following view parts composing the view of object model 'res.partner':\n * res.partner.form\n\nEither you wrongly customized this view, or some modules bringing those views are not compatible with your current data model")
2013-04-08 13:33:13,173 5956 INFO dev8 werkzeug: 127.0.0.1 - - [08/Apr/2013 13:33:13] "POST /web/dataset/call_kw/res.partner:fields_view_get HTTP/1.1" 200 -

What have I done wrong?

apologies for formatting here - not easy to do on this forum.