When the roof stops half way down that's the time to reach up into roof and pull your front and side tenting out of the way
Use silicon spray in the future it's lots cleaner
Gas safe heating engineer / plumber if you need any advice just shout.
A bit of white spirit on an old cloth would do fine. Its how I did mine. The tent material is an impervious plastic (outside surface only!) so wipes clean pretty well. It can however stain over time so that's the one to watch.