Proceed to Checkout issue

Error message from browser - The page isn't redirecting properly.
Initially referred to here .
I have started a new thread to separate it from the main discussion of the other thread.

Following a trace through the code found that Joomla/Hikashop was in a continuous redirect loop.
This happens both with a checkout link from the Joomla menu and proceed to checkout button in the cart.

The URLs look like this:

Proceed to basket button - http://.../component/hikashop/checkout?Itemid=112
Joomla Menu - http://.../component/hikashop/checkout

// global $Itemid; ** Remove this line **
$redirect = false;
$ssl = false;
$new_item_id = $_REQUEST['Itemid']; //$Itemid; ** Change this line **
$itemid_for_checkout = $config->get('checkout_itemid','0');
if(!empty($itemid_for_checkout)){
  if($new_item_id!=$itemid_for_checkout){
    $new_item_id=$itemid_for_checkout;
    $redirect = true;
  }
}

This might be relevant: forum.joomla.org/viewtopic.php?p=2111214
But then I have the same problem with both PHP 5.3 and 5.2 (and different machines).

Checked and I did have it wrong - corrected but still no success.
I have uploaded a stripped down test site to a publicly accessible location.
Stripped out my template changes.
Reinstalled hikashop code.

Access details sent separately in an email.
Included mySQL access details in case this is a data issue.
I have no problem with going back to a complete clean start if thats needed, but while its in this state better see if there is anything useful which can be learnt.

Listed below test steps and results (* = unexpected behaviour).

*(a) Click on add to cart - shows as full cart.
(b) Refresh page now shows as mini-cart.
*(c) Click on cart - get 'The page isn't redirecting properly'
*(d) Hit back button - click delete icon - mini-cart still shows item.
(e) Refresh page mini-cart now empty.
(f) Goto Menu: Shop / Products / Aquariums
(g) In central region click nets link - displays OK.
(h) In left region click Aquariums.
*(i) In central region click nets link - No display.
Expected to be same as (g).
*(j) In left regision click nets link - No display.
Expected to be same as (g).
(k) Goto Menu: Shop / Checkout - Displays OK.
*(l) In central region click nets link - No display.
Expected to be same as (g).