Hi. Need some advice. 18 months ago had new upvc windows installed, now need to update bathroom; new suite and re tile. My husband informs me that our new window unit is sat on the old tiles around the window sill, which I want replacing. He is adament that the old tiles cannot be removed without interferring with the window. Please could someone advise me on how to 1. replace the tiles and 2. cover with new tiles. Thanks.