TUPE, service provision agreements and a flock of chancers.of

[DisgraceToTheYChromosome]

My agency is losing their SPA with our major customer. The new provider, even before handover, has breached TUPE by approaching staff for personal details, trying to assign shifts so that they can invoice instead of my agency, changing pay rates downwards and trying to get us to sign contracts on unfavourable terms (umbrella vs. PAYE). Given I have 6 years with my current agency and over 2 years of continuous full time work with the customer (we like each other and bend over backwards for each other), what are my chances at tribunal? There is no question of TUPE being observed after handover. Thanks.