the exhaust front box is just that, a front box silencer. The cat is the collector on the end of the 4-1 exhaust manifold and has a lambda probe fitted to the inlet and outles sides of the cat (yes the inlet one is almost hidded unless the undertray os off).
There is a complaints procedure for mot failures and the missing cat is a likely candidate for an official candidate unless your manifold has been off and modified.
Brake lines and hose fittings should be free from corrosion but, unless the pipes are pitted, a quick rub with a wire brush and a layer of waxoil would likely be suitable unless theres been advisory notices on previous mot's. If this is a first mot, i think its strange to need new lines.
