Custom UITableViewCell not showing content - ios

Question

I'm having major issues trying to get a custom UITableViewCell show any custom labels/controls. I have a similar project using same code and it works perfectly...the only difference is I use the table cell in a UITableViewController, as opposed to the problem page where I use the table cell in a UITableView embedded in a UIViewController. . Some searching of stackoverflow has suggested the following issues, all of which I have set up correctly:
1) CellIdentifier in tableView:cellForRowAtIndexPath: matches the storyboard identifier
2) All IBOutlets are connected properly
I suspect it may be something to do with the way I load the page (I do lots of page loading in viewDidLayoutSubviews method as I use storyboard autolayout and so I need access to frame sizes etc which isn't available in viewDidLoad)
Any suggestions?
Andy
EDIT: By the way it works perfectly if I use a standard UITableViewCell and instead of my custom label just use the cell.textLabel.text = #"..." etc. It seems to be something related to my custom cell.
viewController.h
#interface ViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>
#property (nonatomic, weak) IBOutlet UITableView *tableView;
#property (weak, nonatomic) IBOutlet UIView *flipContainerView;
...
#end
viewController.m
#implementation ViewController
#synthesize tableView = _tableView;
#synthesize flipContainerView = _flipContainerView;
...
- (void)viewDidLayoutSubviews {
self.tableView.frame = CGRectMake((self.flipContainerView.frame.size.width / 2) - (self.flipContainerView.frame.size.width / 2),
(self.flipContainerView.frame.size.height / 2) - (self.flipContainerView.frame.size.height / 2),
self.flipContainerView.frame.size.width,
self.flipContainerView.frame.size.height);
...
[self.tableView reloadData];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"List Cell";
ListCell *cell = (ListCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (cell == nil) {
cell = [[ListCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
cell.testLabel.text = nil;
cell.testLabel.text = #"test value";
return cell;
}
ListCell.h
#interface ListCell : UITableViewCell
#property (nonatomic, weak) IBOutlet UILabel *testLabel;
#end
ListCell.m
#import "ListCell.h"
#implementation ListCell
#synthesize testLabel = _testLabel;
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
// Initialization code
}
return self;
}
- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
[super setSelected:selected animated:animated];
// Configure the view for the selected state
}
#end