If your happy with the outcome then fine.
I'd be straight with him and tell him you spoke to TS and ask him to level with asking why you would want to replace it. They might have found the car is proper monster with other work needed doing and possibly a money pit. It happens.
I had similiar dealings in July when I bought a BM'er. A month later it needed a new sensor on the inlet manifold and power steering pump and they pulled the "wear and tear" line with me, but we could go halves. Like fuck! I didn't pay retail money for a trade deal to be left at the side of the road. They replaced the parts.
If it's a lemon then let them have it back IMO ....