The council's deputy leader Cllr Geoffrey Williamson said "extraordinary circumstances" had forced drastic changes to the arts centre project.
Bishop's Stortford Arts Forum's letter to all 50 East Herts district councillors ahead of Thursday's crunch extraordinary meeting.
"Council has not carried out any analysis of the extent to which its new version of the ORL scheme will have an adverse impact elsewhere in the town."
Colin Woodward secured pledge to relocate stone elsewhere in precinct ahead of Bridge Street works to accommodate new TK Maxxt.
£15.5m stand-alone cinema-led arts centre, costing around half of original vision, has emerged as East Herts' favoured plan for town centre site.
Grenfell Tower contractor Rydon identifies 'inconsistencies' in concrete used on residential building at Northgate End site.
ORL working group launches survey as part of bid to get East Herts Council to reconsider its plans for prime town centre site.
Columnist Chas Gill returns to defend South Mill Arts after it came in for criticism from arts groups calling for Old River Lane to be put on hold
Future of controversial scheme for heart of Stortford will be decided at extraordinary meeting of East Herts Council on March 18, not on March 2.
"Project team will maximise outside space to provide summer theatre, concerts, big-screen sports events and seasonal activity such as ice skating."
East Herts Council leader focusing on original rationale for ORL scheme: "The driving force for an arts centre was to refresh the town centre."
Press and public will be excluded when East Herts councillors debate how ORL project must change in wake of Covid-19 pandemic.
East Herts Council is building a six-level multi-storey as well as a four-storey structure with commercial space at ground level and 15 flats above.
Local Labour Party wants East Herts Council to investigate whether there is scope for the site to be used for a further education facility.
The list of 600 names, compiled by Labour, Liberal Democrats and Greens, has been handed to Conservative-controlled East Herts Council.