Recently some DRS 66s have been receiving a very plain blue livery with relatively small DRS logos/insignia. Is this a possible indication of them not being part of their long term plan? They have after all already let go about 20 of them.
You mean the very smart livery that's a million times better than the original Compass-mish-mash on the 66s?!
They may have let 20 go, but then acquired a further 19, so it's not as if DRS are not committed to Sheds at all. Wiki has a procurement summary, which I've no reason to doubt (on this occasion).
Direct Rail Services (DRS), a subsidiary of British Nuclear Fuels (BNFL). In 2002, DRS ordered ten Class 66/4 locomotives (66 401–410), employed on new Anglo-Scottish traffic, some with Stobart Rail. In 2006, ten more T2 specification units (66 411–420) were delivered, a further ten (66 421–430) in late 2007, and four more (66 431–434) in 2008.
After the first twenty Class 66s operated by DRS were transferred to Freightliner and GBRf, leaving just 14 in their fleet, DRS leased the five former Fastline Freight locomotives.
https://en.wikipedia.org/wiki/British_Rail_Class_66#Direct_Rail_Services