If goods are provided as part of the service, then they must be:
- as described
- of satisfactory quality
- fit for purpose
There is a strict liability on the supplier of the goods. So it is irrelevant whether or not the supplier knows they were faulty when they installed the goods.
If any of these implied terms are not met then the law will treat this as a breach of contract and you may be entitled to compensation, often in the form of a repair or replacement or an appropriate reduction in price.
Normally you would be expected to allow the supplier to rectify the problem first, unless you can justify why he should not do the work (for example, the work he did left your motorcycle in an unsafe condition.)
If the part which was supplied with the work done was faulty or incorrectly fitted or installed, then you can ask the supplier to repair or replace them free of charge.
If it is impossible to repair or replace the parts, or if this would cost an unreasonable amount when compared with other remedies or put you at a considerable inconvenience, you can ask for a full or partial refund.
You may also be entitled to compensation for any consequential losses and out-of-pocket expenses.