Colossus did not influence ENIAC.

However, there is a connection between British electronics and ENIAC, which is the same, but happened in parallel, with the connection between earlier British electronics and Colossus.

During the decade before WWII, several fundamental circuits of digital electronics had been invented in UK, e.g. several kinds of electronic counters and the Schmitt trigger.

Those circuits have been invented mainly for use in experiments of nuclear physics and elementary particle physics, e.g. for counting events from radiation detectors, for which the existing mechanical counters and accumulators were too slow. The first digital electronic circuit, the Eccles-Jordan trigger, had also been invented by British physicists, but another decade earlier, at the end of WWI.

The British digital electronic circuits were a source of inspiration for the circuits used in the first (special-purpose) digital electronic computer, the Atanasoff-Berry Computer, which was built at Iowa State University immediately before WWII (the published British research papers were explicitly quoted in the ABC design documents).

In turn, the digital electronic circuits used in the Atanasoff-Berry Computer were a source of inspiration for those used in ENIAC, because a member of the Mauchly-Eckert team had visited the designers of ABC, inquiring about its components, even if later they did not credit any source of inspiration for the ENIAC design (the Mauchly-Eckert team founded a startup for making electronic computers, so they were wary of providing any information that would make their work appear as less original and not patentable and they were also extremely annoyed by the publication of the von Neumann report, which explained for everyone how to make an electronic computer, so it created very soon a great number of competitors for the company of Mauchly and Eckert).