According to National Rail Enquiries (NRE), Greater Anglia will take folding bicycles on replacement buses:
A portal into UK rail travel, including information on ticket purchase and promotions, train times and delays, and more.
www.nationalrail.co.uk
Buses will run from Brampton to Saxmundham in one direction (stopping at Halesworth and Darsham on the way) and from Brampton to Lowestoft in the other (stopping at Beccles and Oulton Broad South on the way). At Saxmundham, you then have a train every hour on to Ipswich. The link to the times at Brampton are below:
Train information at Brampton (Suffolk) all day on 24/10/2020. From Realtime Trains, an independent source of train running info for Great Britain.
www.realtimetrains.co.uk
As for where the buses pick up, I'm not too sure. NRE normally indicates the pickup point but they've not included that info on their website, instead pointing you to ask at an available help point once at the station.