does anyone on here know if mot testers are allowed to scrape off underseal?.... ive recently undersealed my wheel arches and ive been told that mot testers are suspicious of underseal on old cars and may start scraping it off asuming that your atempting to hide something, is this true?

i dont wand my nice new underseal scraped off when ive just spent so long putting it on.

They don't like it and may fail you if you over-use it. However, it's criminal damage if they start trying to scrape stuff off. Same reason why they can't touch welds that you've done yourself (but they can still lightly tap it with the hammer of truth)