So, I replaced the screen on our Avanti Flow yesterday. Whilst the guides I looked at on various other sites are undoubtedly factually correct, they all are, how shall we say, somewhat light on detail. I thought I would post my pointers, and some pics.
First off, dealing with the mesh covers. As other sites have pointed out the front and Sub Speaker grills are just interference fits. You would be advised to use either a guitar pick, or some of the plastic tools used in Mobile phone screen replacement kits to help get them out - unless you have very long and strong fingernails.
Secondly, remove the rear panel. It helps in getting more light in to see what is what. You do not need to remove any of the leads or cables from the rear panel. Watch out when you remove the speaker (4 bolts for the plastic trim which then reveals the 4 bolts holding the speaker - it is magnetic, of course and will try to attach itself to the metal insert in the wooden frame of the Radio. Remove the wadding - but with care, lest any of the wires or ribbons get caught. Definitely remove the screw holding the white cable holders - this will give you a lot more freedom when it comes to addressing the front panel.
Remove all the screws in the front panel (8 of them). Note that the screws are actually in parallel, so not following the curve of the front panel - remember this or you will round the heads of the screws. Gently pull the front panel out - but as the white ribbons start to extend, gently remove the tape which holds them together. You may also want to move the cables through the white plastic holders to ensure you have enough room to get at the PCB's.
Remove the first pcb, but leave it where it is. You will now be able to access the 4 screws to the second pcb. Make sure you are using small Philips screwdrivers - there is not much space, and you will need to access via the sub speaker cavity. The screws all have a touch of sealant to stop them vibrating loose, but this is easily broken.
You will almost certainly need to turn the unit over to gain access to the pcb screws.
I chose at this stage to remove the 2 gold ribbons which connect to the Screen pcb, plus the thinner white one on the other side. Take a photo, so you know where they go. As suggested on another site, probably best to use thin nosed pliers, with electricians tape round the jaws for ribbon removal.
There are 6 screws holding the Screen PCB and the mounting.
Once you get this out, make sure you know exactly how the ribbon folds and which may up the screen actually fits. Gently remove the foam cover from the plastic housing with your finger nail. Do not use a knife or screwdriver, as you may damage the pcb. Retain this so you can glue it back after fitting the new screen.
I had to trim the plastic housing to allow my replacement screen to fit. Basically there are 2 small tabs inside the housing which I had to remove on one side with an Exacto knife. Perhaps I was unlucky, just saying that your new screen may be 1mm wider than OEM.
Fitting the ribbon back into the screen pcb was a bit of a fiddle - again use long nosed pliers with tape on the jaws.
Refit the second pcb, and attach the ribbons. Note that the cables to the front speakers have a hard plastic and foam "gromit". These need to be reattached to the pcb posts. If you don't do it his way, you will struggle to get the front panel back in the case. finally screw the first pcb back in.
The front panel should now slide back in (snuggly).
Gently fold back the white ribbons (I didn't bother taping them back up), push through the cables and reattach the white cable brackets, which is a bit fiddly.
You can then refit the speaker (the wires are sized to fit the correct male/female) and trim, rear panel and the grills. They may have distorted slightly when you removed them, just be patient.
Switch on and enjoy a super bright screen!
Good luck. It took me over 2 hours to fit mine. I reckon I could do it in under an hour having done it once already. Hopefully I will not have to do it again for a very long time.