I have found some Trem wheels in stock for up to 180kg. Best part is they are the cheapest I have seen. £109.99 Link below.
Trem Launching Wheels - From £99.99 - Gael Force Marine
Does say upto 180kg so must be the right ones. I phoned the order through as there is a choice of the smaller model too, but when you change the model the stock number didn't change on the website. Also wanted to be 100% on them having them in. Have been told they have one set left so if Dino is still after some, give them a ring. P&P reasonable at £6.99.