We've just paid the deposit on some grey external/white internal aluminium bifolds. Managed to find a company who had one on display so got to have a good feel for how it all worked. I couldn't bring myself to buy one that I'd not seen! It's just a shame very few companies who sell them have showrooms, out of the 8 I rang only two could show me their product!

Hello, if you don't want sight lines then I wouldn't have Crittall to be honest (unless you wanted Crittall without the cross bars of course?? as they are super busy and won't give you a clear view of the garden) We opted to go for bi-folds with slimmer sight lines and wider panes so there would be less lines. On your size opening, it would take 3 bi-fold panes which means the central one is just glass. If you had sliding doors then you would likely have 2 panels with the bar being right in the middle (unless you can slide them into pocket doors!) Bi-folds - they even do frame-less bi-folds now or ones with the lines super narrow so I would get prices for those. It also depends on your garden - as you say, because we had the bi-folds leading directly onto a patio area. If you have to step down then the garden will feel quite separate anyway and so you don't benefit from having an open 'room' as you would with a semi flush or flush threshold and bi-folds doors. In that case, Alu french doors with side panels that don't have all the cross bars would likely be the cheapest option for you.

Hi Adam, we also looked at both sliding doors and slide and turn for our opening and were shocked at the price of the slide and turns. One thing that a few designers and window providers said to us was that essentially slide and turn doors (or bifold doors) look better when they are open, and sliding doors look better when they are closed (as they tend to have fewer panels and so less view is blocked by pane). As we are based in London, where for most of the year the doors will be closed, we were advised by everyone to go with sliding doors. (NB our opening is wider, so it was a difference between 3 sliding door panels or 6/7 slide and turn panels).

Hi! A belated thank you to everyone who helped me finally make a decision! I went with a 3 pane sliding door (on a 3.7m opening) allowing me to open over half the width. I figured that with bifolds you would still have the frames stacked to one side which takes up a chunk of the opening as well. I chose the XP Glide from Express Bi-folds. Have found them professional and easy to deal with, we are just awaiting delivery now! The only bug I had is that their choice of handles were pretty basic, either a chunky (in my view an eye sore!) steel bar or a regular lever handle. They only come in black, grey or white! I was initially going with a very sleek 2 pane sliding door from Ultraline that had an integrated handle within the frame but the cost was too high for me to change it to a 3 pane. If I had the budget though I would have gone with them instead. Express Bi-folds do a slimmer framed option than XP Glide, I think it is called XP Panoramic. The 3 pane was more than Ultraline I think though. The consultant at Express-Bi-folds also advised against slimmer framed bonded glass options as if for any reason you damage the glass you have to replace the whole frame as well which is a major structural headache. Most slim framed options use this method though (as opposed to beaded - correct me if I am wrong!) so I would have chosen to ignore his advice if my budget allowed :-)