Me too. Ours goes in for the same thing on an Ace Jubilee Statesman.There were 3 cracks on the top part so I drilled a hole at the end of each one and covered with UPVC beading but then it cracked near the plug hole.
Rick, I had the shower tray replaced after one year on my Ace Jubilee Viceroy, some areas of the tray are extremely thin. Looks like it may be a common problem with the Swift group vans.
Further to Rich's comments there may be hope. When the dealer looked up my replacement shower tray it was discontinued on the old part number.BUT it was listed as a new part so lets hope its new and improved.The price for the shower tray(if not warranty) was