Right I have this as my context_object on my map entry point

{
  "recordType": null,
  "id": "55",
  "values": {
    "GROUP(custrecord_partnumber_item)": {
      "value": "546669",
      "text": "053 : 53-WF-03BS"
    },
    "GROUP(custrecord_partnumber_brand)": {
      "value": "5927",
      "text": "3M"
    },
    "GROUP(name)": "OCS CS-51"
  }
}

but when I use

var context_object = JSON.parse(context.value);
            log.debug({title: 'JSON Parsed Context.value', details: context_object});
            var item = context_object.values["GROUP(custrecord_partnumber_item)"].value;
            log.debug('itemid', item);
            var brand = context_object.values["GROUP(custrecord_partnumber_brand"].value;
            log.debug('brandid', brand);
            var opn = context_object.values["GROUP(name)"];
            log.debug('opnvalue', opn);

it only gets to the 2nd log and doesnt go any further. Any one have any ideas? (edited)