In this poem, Wordsworth expresses his intense and passionate love of England, his home country. He starts off by saying how that any time he has spent travelling in foreign locations has only served to heighten this love that he has for his homeland and to remind him of memories that are incredibly cherished and sum up what England is to him. The quote you have highlighted to the "English fire" comes in the third stanza that reads as follows:

Among thy mountains did I feel

The joy of my desire;

And she I cherished turned her wheel

Beside an English fire.

The "English fire" is therefore part of the image that the speaker uses to represent his love of England, and is intimately associated with the mysterious figure of Lucy, who is the love refered to who turns her spinning wheel in this stanza. Clearly the way in which the words "English" and "fire" are placed together captures the way in which England and the warmth and hospitality of an open fire are linked together.