You can ASK the bike shop whether they have a means of resolving it but they are under no obligation to do so.
I’d disagree with this, if the forks have been serviced to schedule then they would be expected to be fit for purpose, and to last an acceptable amount of time (they grey areas of the argument). It is the retailers responsibility to suck it up when things to go wrong (hence the sale of goods act).
Theres also the section of not being unduly inconvenienced in having the issue resolved (by the retailer) which 6 weeks would push in a normals persons opinion (what the act is judged by).
How you actually go about it is a different matter, rushing the shop waiving acts in the air and screaming for instant satisfaction would get anyones back up. Politely pointing out that you have spent a considerable amount with them, and as such they have a responsibility to ensure you are satisfied would be appreciated, and no doubt result in a happy / repeat customer.
Start with the latter and see what they suggest, start hinting towards the former if they start screaming their responses …